One-Shot(s) Man
by Old Beginning New Ending
Summary: A series of one-shots revolving around the strongest hero and his disciple. GenoSai (Canonverse, AU, AR) Re-post from Ao3
1. Index and Previews: Vol 1

****Index: Volume 1****

* * *

 ** **1 Punch**** : Omega (or Saitama really should have changed the locks; Omegaverse with Omega!Saitama) ****NSFW****

It also didn't help that the cyborg had gone stock-still after releasing a noise reminiscent of a circuit breaker blowing a fuse. And with Genos just standing there, slack-jawed, mouth hanging wide open, and eyes practically flashing error messages, the only reasonable thing Saitama could do was this: absolutely freak. "For the love of god, __this isn't a free show!__ ** _ ** _GET THE FUCK OUT_**_** _ _!__ "

 ** **2 Punch**** : Alpha (or Genos wants what he can't have; Alpha!Genos)

Saitama was strong: the personification of absolute control and power. Omega or not, he didn't need anyone— didn't __want__ anyone. Let alone a defective alpha like Genos.

 ** **3 Punch**** : Take the Lead (or why Saitama can't give what he doesn't have)

" _ _You should— you__ deserve _ _to know why."__ Of what an empty heart can be, a dull metronome that only keeps time and never plays in tune.

 ** **4 Punch**** : Flick of the Wrist (or an HP!AU with Hufflepuff!Saitama and Durmstrang!Genos set during the Triwizard Tournament [and the Yule Ball])

" _ _Will you accompany me to the Yule Ball?" "Eh? Oh sure..."__ By the time the question registered in his mind, Saitama found himself spewing his drink all over King's hand-knit Christmas sweater. " _ _You know, you should really think before you speak,__ " King muttered dryly, tone a complete contrast to his damp wardrobe. He shot a glance at the retreating figure of the strange blond who had just (successfully?) courted his friend.

 ** **5 Punch:**** Reversal (or an AU where Genos is the 25 y.o. Hero alongside his reluctant disciple, 19 y.o. Saitama; Saitama is still OP but Genos has absolutely no idea)

 _ _"So, you want to be a hero?__ " " _ _Well yeah. For a hobby, I guess."__ Golden eyes narrowed at the slight boy before him, unruly mop of black strands and eyes that belied a hollowness one would associate more with a middle-aged man undergoing a midlife crisis rather than a teenager at the cusp of adulthood. But still...the boy had potential. And as far as Genos saw, the boy had no one else to turn to. __"I see...to undertake such a goal, you need proper guidance. Very well...I accept responsibility." "Eh? That's not really nece— " "Do not worry; it's of no burden to me.__ _It is the least I can do after the damage that befell your apartment._ _ _And from now on, please refer to me as 'Sensei.'" "__ ** _ ** _Weren't you just listening?!"_**_**

 ** **6 Punch:**** Missing Pieces (or Genos recruits the help of his friends to find something very important) ****NSFW-**** ish

 _ _"I'm glad you all came at such short notice." "Whatever. You better make this quick, you hear me?" "It's certainly unusual for you to call on us." "Especially without Saitama." "Where is he anyways? It's actually pretty rare to see you two without each other nowadays." "It seems like a serious matter...should we find him?"__ At that, something akin to a trigger set of an alarm in Genos's mind. _ _"__ ** _ ** _Sensei cannot know about this! Absolutely not!_**_** _ _" "...why?"__ After gathering himself for a moment, Genos turned to them, face uncharacteristically expressive and unnervingly miserable. __"Because...I'm here to ask you all...to help me look for my wedding ring."__


	2. 1 Punch: Omega

Summary:

It also didn't help that the cyborg had gone stock-still after releasing a noise reminiscent of a circuit breaker blowing a fuse. And with Genos just standing there, slack-jawed, mouth hanging wide open, and eyes practically flashing error messages, the only reasonable thing Saitama could do was this: absolutely freak. "For the love of god, this isn't a free show! GET THE FUCK OUT!"

* * *

Saitama knew he was going to get stabbed in the back one day. He just didn't think it'd be by his local pharmacy.

In a purely metaphorical sense of course—in the _physical_ sense, it left him with was an ache in his body, a spike in his temperature, and a string of semi-incoherent thoughts that ravaged his mind. Oh, and speaking of ravaged—he wouldn't mind getting fucked over and sideways right now, yeah that'd be _real_ nice—

See? Exactly what he meant.

"Goddamn…cheap-ass pills—ah- _ahhn_!" Screw the pharmacy. They must've sold him defective suppressants. He squeezed his eyes shut as another wave of arousal coiled in his gut, a very _annoying_ part of him begging for release to ease the heat.

 _Heat_.

God, he was going through a rough one. After months of staving them off through medication, it finally came to bite him in the ass; he hates them. He hates how they made him feel like fire was thrumming through his veins, burning the vessels beneath his skin as his body greedily lusted for someone, anyone, to fill the emptiness that seemed to amplify with every flash of desire to be _**taken**_ and _**claimed**_ —preferably with a _thick, **long**_ —

"F- _fuck_!" A mewl escaped his lips, the fingers in his ass and the hand on his cock no longer enough to bring him towards satisfying relief. Sweat clung to his skin, hazy eyes with a feverish daze narrowing in annoyance as he scrambled out of his sheets and towards the closet. Along the arduous journey across the room, Saitama caught himself along the fine lines of pulsing excitement and crushing mortification. Don't get him wrong—he never hated being an Omega.

He just hated the things that came with it.

Still, heats were circumvented with the right preparations although not totally unavoidable, at least for the sake of his reproductive health. But like Saitama gave a shit about that. Social hierarchy should have been a major factor in his train of thought, but even that didn't matter much to him; as a male Omega, he hadn't stuck out, remaining unbowed to Alphas and often mistaken for a Beta with his slighter stature. He never felt the need to correct them, not because he wanted to bury his nature away out of shame but merely because he hadn't cared about what he appeared to be in their eyes.

(However, no matter how minuscule the matter, his heart did race a few times when his new roommate ordered and arranged the closet, something akin to the unease of the certain awkwardness to follow if Genos ever caught his little…arsenal in the unsuspecting box near the back.)

No…those things weren't what he hated about being an Omega at all. And when Saitama retrieved the box buried behind old shirts he hadn't worn since before his debut as a hero and his one suit that never lived to see an office desk, he _still_ couldn't tell whether the flutter in his stomach was from anticipation or nausea.

His mouth went dry at the too-familiar feel of ribbed silicon as his slick-stained fingers traced the outline of the large black phallus inside. Saitama groaned as the rapid and delicate sensations in his stomach kicked it up a notch and started banging his kidneys to get his ass in gear to quell the annoyance that was his sex drive.

Down to business it was.

He searched the box for a condom and once he found one, he tore the packet and rolled it over the head of the dildo in such mechanical efficiency despite having been moments away from writhing for desperate release. But still, the clinical approach to it was for the best; it was the only way to ease himself into the unwanted but familiar practice. No, being an Omega was who he was.

But during his heats, he just didn't like what he _became_.

By the time his "partner" had been properly situated (tip pressed against the rim of his twitching hole, slick running down his thighs, and a shaking hand teasing the head slowly into his entrance) " _Saitama_ " officially left the building.

In a purely metaphorical sense, anyways.

Because now, in his wake was a desperate _Omega_ panting and moaning as his lonely excuse of a love-life burned and stretched his walls at a sinfully delicious pace, friction and size filling him so _wonderfully_ as he hit his sweet-spot in practiced, impatient frenzy mere seconds after mewling at the sensation of being completely _full_ , hips moving in a sloppy and powerful rhythm against the toy, the primal thoughts of _more, more, please, Alpha—give more, harder, harder, feels so good, don't stop, don't ever stop, claim, mark, yours, yoursyoursYOURS **YOURS** —!_ as a conjured voice in a deep baritone mindlessly praised him for being such a _good_ little Omega, opening up for him so nicely, body tight and greedy as it hugged his cock so well, making such lewd little noises as his pretty little hole was violated and worshiped at the same time for _his Alpha's_ use, teasing him for being a _slut_ for the pleasure only an Alpha could provide, the salacious bliss of being wholly claimed, _owned_ —

 _ **Mated**_.

And he _ached_ for it: the rough hands pushing him down, the guttural groans and hisses against his ear, the scorching heat of a body above his, the sensation of surrender pulsing from the marrow of his bones to the feverish rouge on his cheeks as their bodies would move in animalistic want, teeth digging into the flesh of his shoulder and neck, bites and bruises littering his skin as a claim for all to see—fingers teasing and tongues playing and lips kissing like sparks of lightning across the planes of his body, the sensation of being _dominated_ , _cared_ for, loved—

 _ **Belonging**_.

And in that _damn_ moment, Saitama started to regain himself. Because no. It never mattered, not _once_ , that each heat left an empty ache in his chest (and his ass) at his status as an unmarked and untouched Omega. It didn't matter that he had been too ordinary, too average to be picked from a crowd, never an Omega whose attention Alphas would clamor for because it was fine; he never gave them the time of day either. None of that mattered because Saitama didn't _need_ an Alpha, didn't need _anyone_ to take care of him during the worst of heats or hold him through the bitter loneliness that crept like shadows and choked him like hot coals down his throat as his hormones betrayed his body in the most unforgiving ways. He didn't need someone to hold him at night and make him feel safe through a wordless touch, a comfortable warmth. He grew strong enough to be independent, to be able to protect himself through dangers and disasters, through chaos and storms. He didn't need to tie his existence to anyone else.

He never had that sort of connection to begin with so it was obvious it was something he could live without.

He could have also lived without the terrifying sound of the door opening and the call of " _Sensei, I've returned from my repairs_ ," echoing through the room with the dramatic effect of something straight out of a grade-B horror flick. And it all happened so quickly that Saitama wasn't sure whether to stop what he was doing or to curse every deity he knew.

The appearance of his self-proclaimed disciple before him should have also been prolonged to fit the mood of inexplicable dread that Saitama was currently registering; or at the very least, Genos should have stalled long enough for Saitama to stop fucking himself with a dildo.

Oh…he was still masturbating wasn't he.

 _Damn it all._

It also didn't help that the cyborg had gone stock-still after releasing a noise reminiscent of a circuit breaker blowing a fuse. And with Genos just standing there, slack-jawed, mouth hanging wide open, and eyes practically flashing error messages, the only reasonable thing Saitama could do was this: absolutely freak. "For the love of god, _this isn't a free show! **GET THE FUCK OUT!"**_

Had Saitama been any other man, he would have missed the way Genos had all but rocketed out of there due to the sheer speed the cyborg had to be going to clear the premises. And had Saitama been any other man, he would not have made a sizeable hole in the floorboards where his fist slammed down as he asserted his right to whack off in peace.

God _damn_ it all.

=-=-=-=-=- **Extra** -=-=-=-=-=

"Uh…yeah, sorry. I've been meaning to tell you…about that." Man this was awkward; so very awkward.

"No, it was my fault for barging in as I did. My sensors indicated read your increased vitals and so I had thought you were in need of…" A small cough; did cyborgs even need to cough? "Assistance." Besides for modesty, that was.

Saitama gave an inward sigh of aggravation as another spike of arousal tingled all the way down his spine. "No…I had it covered." Not well enough though since he probably traumatized Genos for life. "I mean, I took care of it myself."

"… _would you like any future assistance?_ " Whispered ( _wanting_ ).

Wait, what? "Eh?"

"Is there any way I can be of assistance?" Firmer now; certain and determined.

Saitama hated himself for letting his knees get weak at the sound; this heat was really taking a toll on him. It was fine though; he could live without Genos's cleaning and cooking for a few days. "Nah, but I think it would be a good idea for you to stay with your Doctor for now…until my h-heat blows over."

"Understood. When is the best time for me to return?"

"It should be three days or so…but my cycles are…weird." He nearly winced at the direction of the conversation. "Come back in a week or so." A beat. "I mean…if you still want." Softer; reluctant and mumbled.

"Sensei, your nature changes nothing of how I see you." There was a quaver in Genos's voice and something in Saitama shifted. "I still want to learn from you, live by your teachings, and become stronger. I want to stay by Sensei's side." Crumbling, piece by piece.

"Yeah, yeah…" His throat was dry and the chuckle that he tried to make tripped on its way out of his mouth. "Keep it to less than twenty words, remember? You went over by one."

"I…apologize, Sensei. I shall keep that in mind when I return."

Saitama swallowed. "Sure. Yeah. Bye."

"Goodbye, Sensei."

And by the time the footsteps faded from his ears, a bitter chuckle rose from his chest. _Didn't change, huh?_ Right.

Saitama ought to tell Genos he was a shitty liar one of these days.

* * *

Notes: For simplicity, the heat suppressants can be seen like birth control pills but I'm not going into the intricate details of how they're going to differ (i.e. the effects on mood from birth control, the mechanism of it, and the rigid schedule to keep when taking them, mostly because I can't really see Saitama abiding by the latter's strict guidelines).

"Slick" is the term I've seen most used for the natural lubricant Omegas excrete during sexual arousal [usually only during heats] to ease penetration, akin to vaginal lubrication.

Also, I wanted to point out something: heats are focused, not just on sex, but on breeding too—something that Saitama really has no care for. And although Saitama believes that he 'loses' himself and becomes a whole different person while undergoing heat, his 'primal' wants are not towards reproduction but are focused on the psychosocial effects of being mated.

Ah…more of Genos's side in the next chapter c: Hope you enjoyed reading this one!


	3. 2 Punch: Alpha

Summary:Saitama was strong: the personification of absolute control and power. Omega or not, he didn't need anyone— didn't want anyone. Let alone a defective Alpha like Genos.

* * *

"Uh…yeah, sorry. I've been meaning to tell you…about that." His Sensei's voice wavered ever-so slightly from behind their shared apartment's front door. Before Genos even processed his movements, he caught his hand gripping the doorknob tightly, dents forming beneath his hand.

It should have been easy to let go but it was also just as easy to turn the knob; easy to step inside to find his Sensei, panting, feverish, and sensitive from heat; easy to gather the older man in his arms, to hold and soothe him until the aches and trembles subsided; to quell the anxiety and need coursing through him, to murmur words of praise and worship until his Sensei's ears turned red from embarrassment; easy for Genos to forget himself in the moment, placing a daring kiss to his teacher's naked shoulder, peppering a trail to his neck until he reaches the jumping pulse of a jugular, erratic from aching want and the terrifying tenderness of the moment as Genos would bite, lick, and tease, something very vital to his thought-process short-circuiting as he loses himself in the sweet, enticing scent of his Sensei—a heady and honeyed aroma that lingered beneath the smell of sex and sweat— as his Sensei gasps and holds him ever-closer, shivering in need, temptation incarnate as he grips Genos by the hair and smashes their mouths together, lips moving sloppily against one another as Genos devours the electric flavor of his Sensei—an essence of raw power and a zest of storms and natural disasters—coming undone as he hungers for _moremore **more**_ of the man in his arms, to mark, to _claim_ , to **_mate_** —

Genos released his grip, hand trembling from the amount of mental effort it took to complete the simple task. "No, it was my fault for barging in as I did." His core whirred noisily in his chest cavity, seeming to protest his actions. Genos ignored it and continued his explanation. "My sensors read your increased vitals and so I had thought you were in need of…" Thoughts flickered—too many of them, mostly reruns of the salacious scene he arrived to of his Sensei spread out and feverishly impaling himself on a cheap sex toy as he wordlessly glanced up at Genos with desperate, lust-hazed eyes, alluring, tantalizing, _inviting_ — "Assistance," Genos ended lamely with a sputtering cough.

"No…I had it covered." His Sensei sounded distressed once more and Genos fought the urge to incinerate the door between them. "I mean, I took care of it myself."

" _…would you like any future assistance?_ " After the words left his mouth, Genos quietly wondered if something actually had malfunctioned.

"Eh?" Genos was grateful his Sensei was unable to sense his growing panic.

"Is there any way I can be of assistance?" Genos tried again, finding his voice and sounding sure. Because he did want to help his Sensei. Help him with _each_ and _every_ want and need—

Genos hated going to see Doctor Kuseno again so soon after his repairs but he felt that this one might be urgent. "Nah, but I think it would be a good idea for you to stay with your Doctor for now…until my h-heat blows over."

That would be for the best; after all, Genos just barely restrained himself from bulldozing the door down after hearing that small stutter in his Sensei's voice. "Understood. When is the best time for me to return?"

"It should be three days or so…but my cycles are…weird. Come back in a week or so." A beat. "I mean…if you still want." The panic levels Genos was registering immediately spiked at that.

Because this was his Sensei, undoubtedly the most powerful being in the world in Genos's mind and unquestionably the most amazing person Genos's eyes; his Sensei, a kind and humble man that stood universes apart from Genos in measures of strength, a pinnacle that he, nor anyone else, could ever reach; his Sensei…an _Omega_ —a beautiful _Omega_ of unparalleled greatness of heart and heroic exploit. Genos had long been enamored by his Sensei's strength and strength of character; this was merely another facet of his beloved teacher that Genos had uncovered, something to place in his notes alongside his Sensei's quirk of stopping to pet every passing stray animal he sees and his inability to correctly separate his chopsticks.

It was just another thing Genos learned and cherished about his Sensei. And he needed to have the man hear it too. "Sensei, your nature changes nothing of how I see you." He said the words earnestly, trying to convey as much of his feelings he could to the proclamation. Even then, tasting the words as they left his mouth, it sounded… _off_. Something the cyborg couldn't properly place, couldn't properly name, latched itself onto his voice, twisting his tone and bending the truth ever-so-slightly. "I still want to learn from you, live by your teachings, and become stronger. I want to stay by Sensei's side." Yes, of course he wanted that. Besides his revenge, he wanted that more than anything.

 _(But he **yearned** for something more—)_

"Yeah, yeah…" What sounded like a raspy cough from the other man thankfully derailed that train of thought. "Keep it to less than twenty words, remember? You went over by one."

Ah…Sensei was right once more. Genos had forgotten. "I…apologize, Sensei. I shall keep that in mind when I return."

"Sure. Yeah. Bye." Clipped; closed.

"Goodbye, Sensei." A mistake that needed to be fixed.

* * *

In retrospect, Genos _should_ have kept the day's discoveries to himself as he entered Doctor Kuseno's lab; buried them away only to have them resurface in the quiet of the night between the strange threshold of his mechanical body powering down to recuperate and when his own mind teetered on the edge of human dreams.

But he had known Doctor Kuseno since he was fifteen and had organic afferent nerves stretching from the tips of his toes to his CNS. He owed the man his life and his unfailing trust.

Surprisingly, it didn't take him very long to explain the situation at all.

Also to his surprise, by the end of it, the Doctor merely hummed and patted him gently on the head with a wry smile. But what he said next not only completely floored the cyborg but also made him eternally grateful that he was able to deactivate any expression of emotion. "Well my boy, I supposed it was about time you've experienced a sexual awakening."

Genos was unsure if his face even had the input for a ' _dying of embarrassment_ ' reaction.

"I've also suspected that it would be your Saitama-sensei," Genos refused to acknowledge the loud whirring in his core at that. "Considering how utterly smitten you are with the man," the Doctor commented offhandedly.

Was his expression actually disabled? Maybe it just got jammed after his brain failed to fully process his mounting mortification as the Doctor continued.

"He is unmated, correct? Unclaimed by another Alpha or Beta?" The Doctor watched him closely, a calculating gaze beneath the fatherly veneer.

"No." It was not spoken with stubborn finality, nor with a sputtering indignance. It was mere fact and expressed as such.

The Doctor gave him a troubled look. "Then I fail to see why you're reacting so negatively to this. You can court him, after all."

The bitter upturn of his lips was the first form of emotion to crack behind the stoic mask he had painstakingly applied. "Because I'm an Alpha?" Silence resounded in the lab, sound dampened by the stillness despite the way the world began to crumble all around him at the choking realization. "An Alpha who cannot protect him?" The thought was almost laughable. "Cannot provide for him?" Monetarily, maybe, but thinking back to when he learned of his Sensei's overwhelming apathy born of solitude and monotony, no, he couldn't; not in the way that truly mattered. "Cannot…cannot give him a family?"

And how could he when he sold pounds of flesh, bone, and blood until only his mind and soul remained for a shiny, _brittle_ weapon?

His Sensei was strong: the personification of absolute control and power. Omega or not, he didn't need anyone— didn't want anyone. Let alone a defective Alpha like Genos. "How could I possibly—"

"Because you are in _love_ with him." Genos was almost affronted by the amount of sheer irritation in the man's voice like the cyborg was missing something very important. It wasn't as though Genos was blind; he had known the other as half his heart long before. "Tell me Genos." At the authority carried in his tone, the cyborg turned to the Doctor. "Do you love him because he is an Omega? Ah, I'll take your insulted glare as my answer." He gave a chuckle. "You know…I didn't salvage your vomeronasal organ— the organ that responds to the pheromones and acts as an accessory to the olfactory senses. Once the pheromones attach to the receptor, it sends the information to the hypothalamus to be processed to release the neurohormones that in turn lead to releasing tropic hormones in the anterior pituitary that then target other exocrine glands—"

"Doctor…"

"Oh hush, just because _you_ have to abide by that silly twenty-word rule," the man snorted, a grain of amusement apparent. "Very well. What I mean to say is…Genos, your nature likely has nothing to do with how you feel towards your Sensei. Therefore it would be unfair to yourself to want your nature to play a role in pursuing a relationship with him."

It eased some of the tension that had been coiling in his gut; even then… "I've never experienced these urges before…not until I learned Sensei was an Omega."

Doctor Kuseno nodded sagely. "True…but you probably never caught him in the midst of a sexual act before either. At least, not in the actual planes of reality." The Doctor mentally noted the angry whirring that commenced; was the going to be a problem Genos would have him addressed later on? Ah well, it's good for the boy to at least have some form of expression for his embarrassment. He's only human after all…and a teenager at that at. The Doctor's eyes softened. "Genos…what is it that you're afraid of? That your feelings for your Sensei might have stemmed from nature alone? Because while I admit that you may have lingering instincts to procure and protect a mate, I doubt its long-term impact on your actions and mentality since you no longer have the effector organs to respond of pheromones."

Genos's gaze lowered to the floor. "So…I am defective." Useless; unwanted.

"No, you're aggravating," the Doctor retorted. He sighed noisily. "Do you think your Saitama-sensei is out looking for an Alpha? Do you believe that because he is an Omega, he is ruled by social standards and expectations?"

"Definitely not." Another fact.

He raised a brow. " _Then_?"

"But then he—he may believe that I only act because I saw—saw him as an Omega. And…it's frustrating…" The whirring started up again, the Doctor observed, as he watched the young man before him unravel at the seams.

 _Still only a boy._

"Because I— _care_ for him so, _so_ much…and I want to…" Hold him, claim him, spend frenzied heats in throes of unrelenting lovemaking…to feel kicks and flutters beneath a rounded tummy—Genos shuddered in longing. "I want to make us _fit_."

"Elaborate. And please…feel free to go over twenty words if necessary," the Doctor insisted softly.

Genos was a genius but even then, it took him some moments to arrange everything together and lay them out neatly for the Doctor, and himself, to understand. And perhaps just a few more seconds after that to admit it all out loud: "Put simply…I am a cyborg and an Alpha…in love with my Sensei, an Omega, but not because he is an Omega. I cannot function as a proper Alpha and he does not feel the need to belong to one. But I…I still want to be a good Alpha for him; I want to be able to give him all he deserves…even if it is unwanted or unneeded. And because of who he is and who I am…he may not return my feelings at all." Softly, as though to escape his own voice, "I fear I am not enough."

Only a human boy caged in a metal machine holding onto his very human insecurities. "So…what will you do then?" the Doctor asked.

"That…" Genos sighed, expression near-unreadable. "Is a very good question."

Near-unreadable except for one who had known the cyborg since he was but a boy with storms beneath his feet and a toxic resolution in his heart. "Being lost isn't the ideal starting point," Doctor Kuseno mused, watching at how much that boy has grown as the inklings of determination gathered in those bright gold irises. "But it's a start nevertheless."

Alpha:  
al·pha  
/ˈalfə/  
noun:  
The first; beginning

* * *

Notes:

Welp…this came out longer than I wanted…but at least I got to write what I wanted to say ^^;

A (long) word on physiology:

The vomeronasal organ is very real and exists in humans but was previously deemed nonfunctional for mating behavior as we evolved as a species; currently, there are studies being conducted to see how functional it actually is to our behavior but as of now, the no new findings have been put into a mammalian physiology textbook :v

Speaking of physiology, I am not sure how much of Genos's brain is left. What I do know is that organs in the brain, mainly the hypothalamus and the pituitary, are part of an axis wherein the hypothalamus receives input to make a change in the body and makes inhibiting or stimulating hormones that promotes the anterior pituitary to make the appropriate tropic hormones that then go to the organ that needs to make the changes (usually to make yet another hormone) and then the change finally occurs.

Example in testosterone: The testes sends a signal (that it's in need of testosterone) to the hypothalamus to make Gonadotropic Releasing Hormone (GnRH); GnRH goes to the anterior pituitary to stimulate production of Follicle Simulating Hormone (FSH; important for sperm production) and Luteinizing Hormone (LH). The latter goes to stimulate the production of testosterone in the Leydig cells in the testes.

What I'm trying to say with this is that Genos has the control center but I don't know if he has the means of creating the effect his brain is trying to make. How can he stimulate production of GnRH when he probably doesn't have testes to send the signal that he needs to make them? And even if he was producing GnRH and LH, where would it go? The last hormone is made outside of the brain (in my example, testosterone) and it is the one that creates the effect on the body.

Psychologically, his need to want to be a functional Alpha for Saitama comes from his own insecurities of how his teacher might react to his feelings. In black and white, it should have been perfect: he's and Alpha and Saitma's an Omega. But he's "defective" and Saitama doesn't even want an Alpha to begin with. He's conflicted with how he should feel and react to the situation versus what in actuality is there. That's why, even as an Alpha, I think his feelings for Saitama wouldn't be the product of his nature, nor would they be completely dictated by his nature. He wants to be able to do these things as an "Alpha" as an expression of his love.

Not only that, but I personally feel like if it made it seem like he was only into Saitama because he found out he was an Omega would cheapen his feelings so…

I swear there's a happy ending somewhere. But for now…I hope you enjoyed reading ^^;


	4. 3 Punch: Take the Lead

**3 Punch:** _Take the Lead_ (or why Saitama can't give what he doesn't have)

"You should— you deserve to know why." Of what an empty heart can be, a dull metronome that only keeps time and never plays in tune.

* * *

He was used to silence. Stillness too, to an extent.

There would be no crowds to cheer him, raucous, vibrant in their exaltations of things people didn't really understand (words like _justice_ and _hero_ thrown around with little meaning behind them except that they were strung together like rhyming lines in a song) and even monstrous roars and blares of noise suffered diminuendo before meeting their coda with but a single punch.

Before, he had filled his tiny apartment with as much background noise as he could, insignificant harmonies without a melody to accompany the piece, a constant reminder of his lonesome world.

But he had Genos now.

 _Hello_ s and _Bye_ s in and out of the door, conversations over dinner and dishes, instructions and directions given on supermarket sales, embarrassingly frequent words of praise and the too-often sound of confusion that followed; an occasional joke on a good day and an occasional grumble when reading the mail followed by the grave promise of a quick death to the sender; a _Goodnight, Sensei_ at bedtime returned with _Night_ before tired eyes closed and a metal body engaged in Sleep Mode; a constancy, foreign and familiar that was suddenly ingrained in every moment of his life.

A tiny world suddenly, abruptly, wonderfully overflowing with words.

Because he had Genos now.

The _'had'_ in this should be emphasized.

Because _relationships_ were tricky little things, an intricate dance with an impossible tune that can't be taught and only felt with every step and a melody built from moments and movements, the small and grand, that passes between two people in the most intimate ways; a natural progression, adagio and andante forgotten in the wake of a disciple's determination, but a fluid transition to form a duet where there was only a cadenza before.

And perhaps, Saitama was a bit lost in it all; his world long fell to silence with only a steady beat by his side. Too lost in the perpetual cadence, he had overlooked the budding crescendo of the strange little melody they had built together.

Before he knew what happened, their tiny universe of words and music climaxed to a fortissimo with _Sensei, I love you—_

And crashed to a caesura with _Genos, I'm sorry._

 ** _Intermission_**

It was quiet tonight; not the relaxed phase between dusk and the hour of sleep he had known for the past year, but one born of a simple mistake that could not be taken back. Of a heart offered and a heart broken as it slipped between unprepared fingers.

"Genos," And Saitama wondered of the strange tightness in his own chest at how the other stiffened in response. Dinner had been taken in silence with two pairs of eyes trained at their plates and conversation retired after a curt, _Thank you._ He hated it. "Can we talk about this?"

A pause. "There is nothing to say," came the reply. Gold eyes still refused to meet his own and that bothered Saitama more than it should have. "When I spoke of—when I spoke to you, I had known the outcome." Resignation. "Please, just give me ti—"

"Knew the outcome?" Saitama frowned, glaring hard. "You were already expecting me to turn you down?"

It was silent again for a moment before Genos sighed. "Sensei said it himself: he is not interested in men."

"Huh? When did I—"

"Before we left for the House of Evolution." That name _sort of_ rang a bell…"You informed Armored Gorilla after you mistakenly believed Doctor Genus was interested in pursuing a physical—"

"Ah, right…that." Saitama blinked, realizing that had been only the second day he knew Genos, a week or so after he had first met him. The tightness was back now, squeezing harder than before. "So…you've had that in your head for a while." It was an ache now.

"Yes." And damnit, why did Genos look at him like a man prepared to meet his mortal fate? "I had known the outcome."

"And…you still told me?" His throat was dry; he very nearly croaked out that response. But he couldn't show that to Genos. Not when he wanted to say— _needed_ to tell him so much.

Gold eyes lowered to the floor. "I was…informed that perhaps revealing my feelings would…" A quaver in his voice, soft, veiled, "At least allow me to move on." Thunderous, unmistakable.

"Oh. I see." He had prepared for the final blow, knowing that whatever his teacher had to say would only drive the hammer to the final nail in the small box where his heart would lie, buried until the longing no longer pained and until he could deliver devotion shorn of ardor.

"I…also had hoped…" He drifted off to silence once more.

Saitama scratches his head, treading carefully before speaking. "That I would have changed my mind about what you heard me say nearly a year ago, right?"

"Yes." And how despicable was it that Saitama was still privy to these broken little hopes? "That day…you also said that the true power of human beings lie in that we can change ourselves." Did Genos think there was no way he could take these stardust wishes and lay them over open wounds?

Because hearing this, Saitama himself was starting to fear that he would succeed in just that. "Well I wasn't wrong." He gave a shuddering sigh, feeling a foreign, leaden weight settle in his chest. "Look…I can't change my answer for you. I don't know if I can be sorry about that, but…" He had to say it—had to make him understand. "You should— you deserve to know why." Of what an empty heart can be, a dull metronome that only keeps time and never plays in tune. "Why I can't return your feelings."

Confusion and hurt was evident in too-human eyes. "Sensei?"

Well…here it went: "I'm not all right, Genos." Looking up, he realized he probably said it in the worst way possible from the panicked expression on the other's face and the crazed look in his eyes—oh wait those were just— "No, put your scanners away! I'm not dying!" Crap. He messed up. Saitama scratched his head. "Maybe that's the wrong way of putting it…uh…" God, he was only ever good at words when thinking of them on the fly. "Remember when I told you that ever since I became strong, nothing really excites me anymore?" A hesitant nod. Saitama took a breath. "Well…it applies to this too." And maybe he should just quit thinking so hard about this; everything he was about to say was the honest truth, after all. "Woman, man, I don't think it would have mattered. My answer would have been the same. Not just for you but for anybody." The honest, _honest_ truth. "I can't give what I don't have."

They said silence could be deafening; it's not. It's really not. Too many thoughts swarmed his mind, too many words unspoken, taking flight just as he tried to catch them as anxiety droned like insects on a summer's night.

Saitama swallowed. "But I do care for you, you know. That's why I'm telling you this now: don't you dare start sulking for the likes of me. I'm not worth it." These words were easy to say; something he had always known and hoped Genos would realize too. "You deserve better. You deserve someone who can receive all your love and return it a thousand-fold."

And he wanted that for Genos. He wanted to see the younger happy with someone who can match his passions, who he could feel at ease with. Saitama may be oblivious at times, but he sure as hell wasn't stupid. He knew Genos placed him on some kind of pedestal, so high in the heavens that his own disciple could only gaze from the earth below. And…that wasn't right, was it? Love should be on equal footing, neither one giving more than the other could take, neither one taking more than he could give. And Saitama would be happy for Genos when he found that. Even if it did mean his disciple's eyes would brighten for another, knowing that his core pulsed and whirred for another, knowing that a much larger piece of his heart would be given to another.

It was fine. So long as Genos would find the happiness he deserved—the happiness that Saitama himself could never give.

"Sensei…" Blond bangs concealed his eyes and Saitama prepared for the worst. _"YOU ARE SO FULL OF CRAP!"_

Saitama blinked. "Eh?" Okay, not exactly the reaction he was going for…

Meanwhile, Genos continued to look positively livid, an expression Saitama had seen countless times. "If you're going to reject me, do it properly!" It was kind of scary now that it was pointed directly at him. "Don't you dare hide behind that excuse!"

Oh. This. _Fucking_. **_Brat_**. "Hey, I'm being serious here! And it's not an excuse! Do really think I wouldn't consider your feelings just 'cause you're a guy?!"

Genos hesitated for a second, if only to give him an absolutely offended look. "Yes!"

Saitama felt a vein throb against his skull. "Seriously? After everything that's happened?!"

"So you're saying that you would return my feelings if you could?" he demanded.

Saitama nearly sputtered. "Of course, you dumbass!"

And while his Sensei was busy being offended in turn, he completely missed how Genos's eyes widened and posture loosened. "Despite my being a man?" he pressed.

"Yeah?" Saitama narrowed his eyes. Wasn't this kid listening at all?

"Despite my metal body?" His glare was still intense but at least it didn't look murderous anymore.

Saitama just gave him a confused stare. "Why would that be a problem?"

"Despite the fact that I may never reach your level in strength and may never be the one to give you the fight you've been seeking?" Genos wasn't glaring anymore now either. Small victories, Saitama supposed.

Besides…"When have I ever asked you to do that?" All right, what was Genos getting at here?

"And you're saying…that disregarding the reason you gave, you would otherwise have no problems being with me." He didn't sound angry any longer too.

Saitama was still ticked off, however. "No?" For a genius, Genos sure didn't know how to pay attention. Ah well, at least he kept his questions short for the most part.

And while Saitama was off in his musings, Genos was smiling, shaking his head helplessly at the man he's hopelessly in love with as said hopeless man missed it completely. "Do you want to be with me?"

"Yes? I mean—" Brown eyes widened. Ah, shit. He managed to let that slip after all. Well, there was definitely no turning back now. So Saitama mustered what he hoped was a sheepish smile and not the product of a mess of knots that formed in his stomach. "You're amazing. I'd be an idiot not to."

If Saitama wasn't so used to Genos's various fearsome expressions (the cyborg did have a "resting bitch face" after all), he would have asked about that particularly frightening look.

He should, however, ask about why he was suddenly being pinned to the wall. Or, at the very least, pipe up about the cracks Genos was forming on the sheetrock.

"Hey, c'mon now." He tapped the cyborg's cheek just once, a miniscule part of him amused by the softness of the synthetic skin there. "There's no need for that."

Genos blinked, appearing to have momentarily shut down for a second; well, long enough to lunge across the table and trap his teacher between his arms and a delicate wall that definitely shouldn't be supporting both of them considering the damage they could both do. "I apologize, Sensei. It was a small lapse of control." Ah well. He couldn't say he exactly regretted it either. Especially not with this proximity between himself and his Sensei. He gave the man a tender look and for a moment, let himself feel as though he were holding the man and not just holding him (semi-)captive. But it didn't seem as though his Sensei was completely against it either; he didn't flinch when Genos titled his head down to catch more of his Sensei's handsome face, sharp cheekbones, defined jaw, and bewildered eyes that gazed silently back at him. But what captivated him most of all was the flush of pink that stained his cheeks and reddened his ears as Genos memorized the scene right before him. His chest started whirring again, this time out of silly little bliss; his Sensei was cute when he wasn't trying. Cute…but perhaps not the best at interpreting his own emotions. Placing a hand over the other's heart and feeling it jump beneath his touch, Genos smiled and mentally shook his head. No, definitely not, he thought as he opened his scanners once more.

"Uh…Genos?" Right; Saitama had known Genos had little concept about personal space (regarding Saitama, anyways) but this was a bit out of line, wasn't it? Especially now that a metal hand was very intent in rubbing up against his left pectoral. "Ah…?"

"…interesting," Genos hummed, eyes afire with that crazed look again.

Okay, that was enough. "You can let up now, you know?" Saitama swallowed, feeling the strangest trickles of—what was that, panic?—setting in. It's been so long it didn't feel right giving it a name; or maybe…it was something else altogether.

"Let me kiss you," came the awfully demanding and awfully sudden request.

"Huh— _wait_ , WHAT?" Okay yeah, that was definitely panic.

"Let me kiss you," Genos repeated, eyes blazing with more resolve than Saitama had ever seen. "To prove you wrong." A beat. "Also, because I really want to."

In truth, it was kind of freaking Saitama out. "Prove me wrong about what, exactly?" He squirmed beneath Genos's gaze, refusing to meet his eyes. But they both knew he could have just as easily wrenched free from the loose hold; the fact that he wasn't even turning away from the other spoke volumes to Genos.

"About what you've said. About you not being able to feel anything." God, if only Genos would stop giving that creepy sta— _those were his scanners again, weren't they?_ "Your resting heartrate is normally around 45 beats per minute; in battle, it increases to 90; I've never known it to go above 100." Yep. Yep they were. "Just now, your heartrate has increased to 120."

Saitama tried to appear as affronted as he possibly could. "Well, you are standing pretty close—and you did just ask to _kiss_ me."

Genos gave him a look. "Do you believe it is out of revulsion or fear?" It was partly pressing, partly pained.

Honestly, Saitama wasn't sure which part of it scared him most. "What? _No_! I—"

"Then that must mean Saitama-sensei is excited," he decidedly announced.

Saitama made a noise somewhere between a frustrated groan and a mortified squeak.

All the while, Genos kept gawking at his mouth rather longingly. "Sensei, please do not tell me this is an exercise of patience and restraint."

"Wh— _you were the one who asked for_ —" Saitama groaned, giving up. "Oh for the love of— _fine_! Yes, you can kiss me! Just stop saying embarrassing things!" Genos didn't need anything more than that.

And as Genos leaned in and Saitama's blood pressure spiked, he thought, _What could one little kiss do to him?_ (In retrospect, maybe a lot considering the look Genos gave was enough to make him want to combust on the spot.)

What was a kiss anyways? A simple press of lips. That was it. The meeting of two mouths in shaky, wet contact, lips lightly pursed, the other gently parted, all too aware of the chapped skin at the corner of his mouth. A gesture of affection, greeting, reverence— _love_. It was romanticized way too much in plotlines that seemed to think there was something almost magical about the miniscule exchange a kiss truly was. Cherub-shy and petal-soft. It was nothing.

 _It was everything._

A surge of fire and a flood of rain all at once, blood thundering in his ears and lava in his veins, thoughts and color rapidly falling away until only touch and heat remained, something boiling and budding beneath his skin, lighting up like a thousand lanterns, dizzying and wonderful all at once. And oh god it was the stuff of clichés but he was drowning and drowning and every parting they took for a gasp of heated oxygen only drove the addiction to new heights as their mouths met once more in feverish want.

Genos pulled away, murmuring against Saitama's panting mouth. "Your heart is racing." _God_ , he just loved to talk didn't he? "I can feel it beat right through your skin." Gold eyes darkened as they greedily took in the pretty picture his Sensei made, hooded eyes, rouge cheeks and kiss-bitten lips letting out soft puffs of breath. But the real prize was what fluttered beneath his fingertips. "It's beating for me, isn't it?" _Dumbass,_ Saitama foggily thought, _Of course it was._ "Because you want me." _Also because you're fucking embarrassing,_ something biting quipped in Saitama's mind; but he couldn't argue. "Because you _love_ me." There was a stutter in the pounding rhythm at that and Genos held the man closer, teeth grazing the sensitive skin on his neck. _Despite what you said and despite what you thought, you do,_ Genos mentally countered with a thrill before leaning in and pressing more kisses, determined to mar the smooth expanse.

" _Genos_ …" Was it a plea or a prayer? And after the blond finally complied with bringing another scorching kiss, mouth open to taste and claim, Saitama decided that it was likely a damnation to hell.

He pulled away again and damnit, it took way too much concentration not to go chasing after those lips. "I won't accept 'no' as your answer to me anymore." He traced a defined jaw, tilting his teacher's face to meet his, his own molten gaze inescapable as it bore down on the older man. "I won't, absolutely not." And maybe that's when Saitama should have realized that he dug his own grave; did the exact opposite of what he felt he needed to do, crossing all the lines he wanted to draw between them, and somehow managed to drag himself to his disciple's arms where he wanted to stay. And now, hearing the erratic rhythm in his own ears, the sweat cooling off his skin, and the surge of sheer emotion he could barely bottle, he listened as the crescendo reached its peak in fortissimo once more: "Sensei, _I love you_."

God, who knew those four words were a reprise? Or maybe this whole thing had been a Da Capo all along. Ah well. Nothing ever goes according to plan, does it? Because Saitama was so _lost_ right now. Lost in this strange feeling pulsing through him, lost in what he should say to the expecting disciple holding him like he would vanish in an instant, lost in the way that he had no idea how on earth this could have happened to him, but it did all the same and he knew what he had to do—at least for the moment.

This world was full of mistakes, misinterpretations, missteps, and misgivings. And as always, Saitama only had a vague clue as to how to go about it all.

So he gave a long-suffering sigh; or, it would have been if he didn't feel so lightheaded and—happy?— right now. "All right…But you better not call me Sensei with this, you hear me?" And at the absolutely _dazzling_ smile he received in turn, yeah, he realized, he was definitely happy. "This time, for the both of us, you'd probably be better off taking the lead."

There he went again, looking like Saitama had just handed him the sun, moon, and stars on a silver platter. "Very well, Beloved." Genos either missed Saitama's appalled look or wholly ignored it in favor of trailing more kisses down his throat, adding in a nip or two just to feel the other's heart skip a beat.

* * *

Notes:

In case anyone was confused, no, this is not a continuation of the Omegaverse fics I've recently written ^^;

I recently re-listened to _Fidelity_ by Regina Spektor. And of course… I tried to make something dramatic and I couldn't just let it end there so it became silly instead. Ah well ^^; My last two fics were sort of on the angsty side anyways.

((It should also be noted that I haven't been in band for many years.))

I know that Saitama is capable of experiencing emotion, it's just…probably the more extreme emotions he has trouble dealing with. His passion for a lot of things are gone and I think he feels like he'd be unable to return Genos's extreme devotion to him. It wouldn't be fair for Genos to be in a lopsided relationship. Of course…Genos would disagree. I also don't peg Genos as the "so long as you want even an ounce of me" sort of guy since he at least has the reassurance that Saitama cares for him and would try for him.

I also wanna say that Saitama really isn't meant to be asexual or aromantic here, nor is Genos trying to force him into a relationship. Aro/Ace!Saitama is a popular headcanon for fic writers and those who watch OPM; it's actually my headcanon as well. But what this fic really deals with is someone who feels undeserving of love because they feel as though what they can give in return isn't enough. Saitama worries about letting Genos down—he expressed so before in canon. Not once did Saitama say that he didn't feel the same way for Genos; he downplays his own emotions by saying he "cares" for him although he is perfectly aware of how much he has changed and how much his life has changed for the better since Genos came barging in. And I think Genos has lived long enough with Saitama to know this about him. He sees that he's not the only insecure one between them but at least Genos has never doubted his own feelings.


	5. 4 Punch: Flick of the Wrist

**4 Punch** : _Flick of the Wrist_ (or an HP!AU with Hufflepuff!Saitama and Durmstrang!Genos set during the Triwizard Tournament [and the Yule Ball])

* * *

He heard rumors of the other.

Unsuspecting on the surface, face forever cast with an apathetic gaze and a voice drifting off in a bored tone; a promising young wizard that belied true, focused, and concentrated magical prowess with an aim of his wand.

Or an average student, an unusual person, and an incredible cheat.

Genos felt his jaw tighten as he moved past jabbering bunch, waves of people parting like seas in his wake as he sought the other. Thoughts stormed and wrath flickered in his eyes as the words burned into his memory. His lips twisted to a grimace.

How foolish.

Then again, perhaps he was also fortunate. Doubt enshrouded the one he pursued like November fog; he was obscured by jealousy, slandered by misgiving, fame arrested by anonymity. Genos was among the supposed few that witnessed his truth—the capabilities and potential of one particular student of the Hogwarts School of Witchcraft and Wizardry.

A wizard capable of obliterating any foe with but a single spell—without the crutch of an Unforgivable Curse.

A seventh year Wizard of the Hufflepuff House.

 _Saitama_ , he had told him some nights ago, as the young man walked away from an injured Genos and the remains of a Whomping Willow.

* * *

For his final year, things sure have been a bust so far.

"I can't believe you destroyed it."

Saitama lifted his head from his half-eaten breakfast to give King a very weary and very apparent once-over. "I still can't believe you're wearing that." Honestly—it was _barely_ November. The ugly Christmas sweaters could wait another month.

The larger man frowned. "Like you're one to talk."

"Hey, it's satirical. It's meant to be humorously offensive," Saitama retorted.

King gave him a look. "It's really only _one_ of those things." He chuckled as his friend gave a graceless flop onto the remaining space of the table, irritation visibly brewing. "So…what made you think it was a great idea to kill an incredibly valuable and incredibly endangered species of tree?"

Rolling his head to face his friend, Saitama sighed noisily. "I already told you: I was looking for that dumb horse—the one the groundskeeper says might be lurking around the forest; you know, you'd think with its pointy head, it'd be able to find its way north—anyways, I had to do it for sneaking out too late. And the tree just…caught me off guard." King raised a brow but said nothing as his friend lamely ended the explanation with: "I just reacted."

Reacted huh… _Right_ …

That was definitely a lie.

Saitama wouldn't have gotten into that sort of position. King eyed the other warily, suspicion rising but ultimately decided to drop it. If Saitama didn't want to talk then there was no way to weasel it out of him. There were more pressing issues anyways.

Besides, how many strikes was that now? "How are you not expelled?" As usual, Saitama just sent his friend a nonchalant shrug. King breathed out steadily, pinching the bridge of his nose in an effort to keep the encroaching headache at bay. "I told you it wasn't worth trying to put your name in that Goblet twice."

At the mention of his botched attempt, Saitama grimaced. "I know. I didn't get picked either; so much for that."

Dangerous-looking eyes softened. He had known that Saitama was especially excited for the Tournament. Not for the fame—no. He wanted something to liven him up again. "For what it's worth…you would have done great," King said gently. _It must be lonely at the top._

"Thanks…" Saitama muttered back, feeling just a smidge better but still overall very tired. Fucking unicorn took forever and a half to find.

King hummed. "Too great; you'd probably be disappointed again." He would have no doubt in his mind who would emerge victorious had Saitama been chosen. He also would have no doubt in his mind that Saitama would have just ended up bored by the challenges and hollow victories. Perhaps it was a good thing the name _Saitama_ had not been what the parchment contained as it flew up to the headmaster's fingers, the name that reverberated in an ominous bellow to call forth the Hogwarts Champion.

Still…it also didn't have to be _that guy_.

He was probably past that anyways. King always knew his friend had shit luck; shit luck but still hopeful, at the very least.

Saitama hummed. "You don't know that. The Beauxbaton champion's supposedly strong, right?" Or, at least as far as rumors go. But then again, they were rumors for a reason.

"Tatsumaki?" King recalled a petite woman haughtily proclaiming glory and undermining the rest of the Champions as she _floated_ to her position beside the other participants. "Yeah, they call her the _Tornado of Terror_." And although allegedly powerful, she definitely wasn't a fan-favorite outside of her Academy.

 _Sounds rather lame, really_ , Saitama thought but decided against voicing it. After all, even if he wasn't participating, he could at least spectate and see what the three chosen Champions were capable of. And speaking of Champion…"I hope Panic knows what he's up against."

King didn't even make a move to correct him; after four years of listening to the self-proclaimed _Speed of Sound_ Wizard claim Saitama as his eternal rival (or until Sonic could actually defeat him in a duel; King's money was on eternity though) and Saitama still couldn't remember his name, it was pretty much hopeless at this point. "There's also the Durmstrang champion: Genos," King added. "They call the guy a Demon."

Rumors (and fans) encased the youngest participant; several of his peers boasted of his skill while professors preened of his talent. Nevertheless, the Champion's solemn and serious expression hardly shifted, even when his name erupted from the flames of the Goblet. His aura, however, darkened in menace.

But of course, that didn't even register to Saitama. "Isn't he only a fourth year?" Likely, his friend already forgot what the younger participant looked like.

King shook his head. Had anyone but Saitama achieved his friend's level of power…King didn't know what would come of the world. He was grateful for having Saitama as he is. "That doesn't mean anything—not in this tournament at least." A pause, wide-eyed and obligatory. "Besides…he sure doesn't look like it…"

Saitama cocked a brow. "And how do you know that?" The Great Hall cheered so raucously during the announcements for the Triwizard Champions that Saitama couldn't catch a glimpse of any of them. Then again, King was tall enough to dwarf even their professors.

Was that King's heart beating? "Because he's headed in our direction." Or that. That could be it too.

And as Saitama turned, he realized why his friend's strange cardiovascular condition started acting up again.

Golden irises enveloped by black scleras gazed forward intently with a muted ferocity; a deep-set frown (bordering a scowl) casted upon pale lips like he had just watched his favorite Quidditch team lose the world championship; a confident and brisk gait that promised dire consequences to any obstacles that laid in his path; a stature more befitting a young adult than a measly teenager with broad shoulders and long legs lending to a height probably on par of Saitama's and an overall aura that read _piss off_ and _don't get in my way_. Still, the most prominent thought of the other boy that registered in Saitama's mind was:

 _Oh. It's him._

The second-most prominent thought was one that was shared and voiced by King: "Scratch that. He's coming right at us."

* * *

Saitama really should have guessed why that gaze was so scary—it was directed at him in particular.

This scenario could have gone many ways, but considering the fact that Saitama had (near-literally) saved the kid's ass, he should be a bit grateful. But judging by the intimidating demeanor, it could go just the opposite direction.

That was until the kid stopped at a respectable distance, _bowed_ , and greeted him with a formal: "Mister Saitama."

Right. So 'grateful' it was. Grateful and downright peculiar. "Ah, yeah. Genos, right?" Saitama scratched his head; he was vaguely aware that the area around them fell silent. Save for King's weirdly loud heartbeat that was.

"Yes, I am." At the mention of his name, the blond's scary impression fell away almost instantly. Weird. Was it just him or the kid brightened up way too much at that? "I would like to thank you for your help that night."

Just as Saitama guessed. "A-ah…that. Yeah, it's not a big deal—"

"If it were not for you, I am sure I would not be able to participate in the upcoming events. Due to your heroic actions, I only obtained a sprain and a few scratches minor scratches, leaving me with more than enough time to heal in preparation for the Triwizard Tournament."

O- _kay_ …"Uhm…yeah. Again, it's not a prob—"

"Your strength and skill are unparalleled to any I've ever met before. You are truly a force to be reckoned with. Please, allow me to thank you once again. And furthermore, allow me to apologize for the damaged you've caused for my behalf."

Saitama heard King make a thoughtful noise, eyes no doubt darting back and forth, assessing what must have happened between the two of them that night. "King, don't you—" he hissed before turning back to the Durmstrang student the moment those gold eyes narrowed at his friend. "Again, it's really noth—"

"I've discussed the circumstances to your Headmaster and we've both negotiated fairer terms in regard to your punishment. I've made arrangements to donate another Willow to replace the one destroyed that night through…various circumstances—"

Saitama blinked, partly amazed, partly wondering who the hell was this guy. "Wow. You must be _rich_."* What? From the sounds of it, it wasn't like the kid was really listening to him anyways.

He just continued on, as Saitama (wearily) expected. "However, there was not much I could do with your previous violations for escaping your dorm afterhours and attempting to tamper with school property. So unfortunately, you will have to fulfill your expectations to the school in regards to those breaches in conduct. But still, I hope you find the terms of your punishment lighter from your previous arrangement."

"Yeah, well thank you." He cleared his throat before the other could get in another word. Seriously, the kid needed to calm down. Not to say Saitama was ungrateful. "Really. That's a lot better than what I thought I was going to end up doing." He gazed up at the kid from his seat, meeting those focused eyes with sincerity. "You didn't have to do that." Especially since that meant Genos had to explain what he was doing in the forest too.

The first challenge would be unveiled on the day the Triwizard Tournament officially commenced. That meant that the obstacles the Champions had to face must be kept at the highest level of security to ensure equality and to test the challengers' resourcefulness and vigilance for any assemblage of dire circumstances—an absolute _secret_.

So naturally, all the Champions knew about it.

Or, should have. For anyone who wasn't aware of the passageway to the Shrieking Shack (and that it was where the first "challenges" were currently housed), it might've been a much more difficult task.

He made it easier for Genos, at least. "Mister Saitama was kind enough to take the blame without voicing my involvement. It was the very least I could do."

Saitama frowned, feeling more than a bit awkward at the strange levels of politeness radiating off the younger student. "Look, can you keep it under twenty words or something? And like I said, it was nothing. I'm glad you're okay and you helped me out, so we're even." And the kid just kept on gawping at him, very apparently hanging on to his every word. Right. The levels of awkward were steadily rising. "Also, please don't call me 'Mister.' You're only like three years younger than me."

"Yes, of course." Another bow. "Thank you, once more."

Saitama shrugged. "No problem." And that was supposed to be the end of that but it suddenly registered to Saitama that the kid was still standing there, looking very much like he wanted to say something that just got lodged in his throat and he was currently trying to spit it out without appearing too sudden or too rude. There was a mixture of concern and anxiety written on the seventh year's face as he tentatively asked, "Uh…is there anything else you wanted?"

Genos perked up at that. "Yes. There is." Oh. Maybe he just wanted Saitama to prompt him to speak? Man this kid was weird. But Saitama found that he preferred his talking to when he's just unnervingly standing there. If the look just didn't seem to fit the guy, Saitama would have pegged him for being nervous. Then again, this particular guy hardly screamed _shy_. "I would like to ask you…will you accompany me to the Yule Ball?"

Yep. Not shy at all.

Saitama absently picked up his juice, swishing around the contents of his cup before deeming it still cool enough to enjoy. "Eh? Oh sure…" By the time the question _actually_ registered in his mind, Saitama found himself spewing his drink all over King's hand-knit Christmas sweater.

Genos was entirely unperturbed. "Thank you, sir. I look forward to our evening together."

Saitama could only respond with various gagging noises as the other walked off.

"You know, you should really think before you speak," King muttered dryly, tone a complete contrast to his damp wardrobe. And while Saitama busied himself with attempting to clear his airways, King shot a glance at the retreating figure of the strange blond who had just (successfully?) courted his friend.

* * *

"All right. So why did you really ask to go to the Yule Ball with me?" Because there was absolutely no way he was dragged out here in _dress robes_ and a fucking _corsage_ that Genos got for him and made to dance the fucking _girl's_ position despite being the elder one and made to endure the ceaseless stares and whispers and the creepily intent looks Genos frequently gave him since he walked down the stairs to meet up for the ball just to have it end on a romantic night under the stars.

It was so cliché, Saitama would just keel over and die if it were.

While Saitama was suspicious and more than a bit peeved by the fact that he actually had to be dolled up and appear presentable for the damn thing, Genos was at least agreeable and played along, polite as ever, in this little charade. He dropped it as soon as they were alone at least. "There were some matters I wanted to discuss with you, outside of the prying eyes of peers, chaperons, and…others."

 _That_ caught Saitama's attention. "Others?"

"It was the only way I could ensure that we'd have some privacy." He paused, turning to the snowscape that laid glittering before them under the moonlight; it made sense. Professors were more than aware of what any sort of social event would eventually lead to for hormonal teenagers. Many of them, on the watch for more risqué acts of debauchery, wouldn't look twice at a pair of teens innocuously slipping out of the ball to a vacant but _open_ sector of the castle to bask in the quixotically romantic atmosphere. No, they had bigger fish to fry—particularly in dark corners and the countless classrooms and hidden corridors, nooks and crannies throughout the ancient castle. It was nicely planned, Saitama reluctantly agreed, though still a bit weirded out that he had to pretend to be Genos's date. "Plus," the boy added, softly, almost _timidly_ , "I wasn't interested in anyone else but you."

Saitama blinked. Or maybe not. " _Uhuh_ …"

And as Saitama observed the fact that _yes_ they were currently situated in a very cliché position and the fact that Saitama did dress up, fucking _waltzed_ with the guy, held the kid's hand on several occasions that night, _and_ allowed himself to be led to this horribly picturesque balcony overlooking the bright lights of yuletide cheer basking beneath the inky canvas of the night sky alight with the twinkling of a thousand galaxies,and the fact that Genos was indeed quite red (he had previously attributed that to the sharp drop in temperature)— Saitama…didn't know there was such a fine line between sweet and disturbing.

He (wisely) decided not to dwell on it. "So, what's on your mind, Genos?"

He took a breath. "I want you to teach me."

Genos should count himself lucky Saitama had finished his Party Punch before they started talking. " _Come again_?"

He turned to Saitama, cheeks undeniably flushed and eyes practically flaming with resolve. "I want you to be my teacher. I want to know the secret to your strength." Saitama blinked. Well…that was a first. "The goals I need to accomplish will require me to far surpass the level I am at right now." Honestly, Saitama was speechless; that might've translated to a negative reaction to Genos as the younger student began rambling rapidly once more. "Please! I was not lying when I spoke of your abilities. You are truly the most powerful wizard I've ever come across. I must learn from you to achieve my—"

"Okay, hold on for moment!" The Hufflepuff sighed, scratching his head. Was this about—? No, this definitely wasn't about the Tournament. This seemed too serious—too personal. Still though, Saitama had to wonder: "Kid, what is your problem?"

Genos was giving him that creepily intent look again. "You'll listen to my problems?"

"… _Goddamnit_." Saitama really had no choice.

* * *

"A Dark Wizard controlling a mad golem, huh…Well…I gotta say…that's rough, Genos." It really was. Not that Saitama could empathize with him, but he knew this was very important to the boy. Important enough to drive his thoughts, actions, goals— _life_. All for vengeance. And that made it all the more precarious for Saitama. "But…what makes you think I'm of any help?"

"You're undoubtedly the strongest wizard I've ever met," Genos replied as though it were all so simple due to that one, hardly relevant, fact.

He sighed. "Yeah, I _know_ , you've said that like—"

"And the kindest." Saitama stilled as Genos fully faced him. "You destroyed a priceless plant for a stranger and rival to your school—" The kid has an awful propensity to interrupt him as he just cut off Saitama before he could even open his mouth. "And you took full blame for the incident, just to make sure none falls upon me." He obviously meant well, however, as his expression softened and his gaze turned uncomfortably reverent. "You take no credit for your deeds and instead allow your classmates to take the glory. Hufflepuff is not known for its courage, like Gryffindor. Nor its cleverness, like Ravenclaw, nor for its cunning, like Slytherin." He gave a small smile, innocent and awed. "Hufflepuff is known for their dedication, patience, loyalty, and fairness. Mister Saitama encompasses all these traits."

God, if his face got any hotter, it would start melting snowflakes before it even touched his skin. "That's really got nothing to do with—"

"The troll on your third year." Brown eyes widened as Genos recited, "You allowed one of the groundskeepers to claim your actions of defeating it to make up for their carelessness in allowing one access into the castle."

"What? How—" _How the hell did he know that?_ Saitama wasn't even aware that anyone else besides himself and the groundskeeper knew about it. "Uh, that—"

"The boggarts that escaped your Defense Against the Dark Arts class," Genos continued. "Your professor still hasn't stopped thanking you."

"Erm—"

"A merrow terrorizing the populace of Black Lake—"

"Others—"

"The Three-Headed Dog—"

"Hey now, Overgrown Rover was harmless!" Saitama felt his eye twitch as a sly grin curved pale lips. Groaning and rubbing his forehead in irritation, he dared to ask: "How did you know about them?"

"In certain matters of importance, I've learned to discern a bad source from a good one. And…you have good people that see your true worth." Huh. Saitama wondered who that was. He didn't have time to ponder for very long, however, as there was that bizarre look of deep concentration in Genos's eyes again—the one that made Saitama vaguely uneasy whenever it was pointed at him. "I know at least a dozen more deeds you've accomplished and at least two dozen more that I've yet to confirm."

In truth, Saitama was plain speechless; it didn't even register to him whether or not he should be terribly flattered or rightly terrified.

"Mister Saitama, do not take it lightly when I say that I want to be your pupil—that I want to learn from you." Shit. This kid was actually…"Please, allow me to be your disciple!"

 _Serious_. And that made things all the more alarming.

"Genos…my technique is really all in the wrist," the seventh year tentatively explained, half-heartedly exhibiting the movement. "There's not much I can teach."

His eyes darkened, highly unconvinced. "Please do not joke, Mister Saitama."

So much for that. "Okay, okay—even _if_ I were to agree to this…how would this arrangement work out?" There might've been just the tiniest inklings of panic at the weighty responsibility Genos was asking of him. "After this, you still have two more years at Durmstrang."

"Move in with me after you graduate," Genos suggested (demanded).

"Uh. How about _no_?" Was this kid for real? "Look, Genos…You're like fifteen, right?"

He nodded. "Yes, sir."

"Yeah, don't call me sir," Saitama drawled, wondering if the kid will ever lose that strange sense of formality. "If you start the training I underwent now, you'll definitely surpass me in no time."

For the first time since they met in the Forbidden Forest, Genos actually looked floored. "Really?!"

"Mhm…I only started getting training myself at the end of my third year. And you're already much stronger than I was back in my fourth." If the kid kept going starry-eyed at him, Saitama might just hurl himself off the balcony. "Look, I'll be straight with you: I went through hell to be able to do what I can now. There was a lot of hard work, sweat, tears, and occasionally blood. But I kept at it and…" His voice tapered off, the last of the words drifting off to the open winter air beneath the silence of the still night, truth and meaning falling away to the cold, cold bed of ice and death below. "It was worth it in the end," he forced out. The words he built in their place burned on his tongue and scorched his throat as he gave them voice. No, no—that was a bitter, bitter _lie_. He had never felt _emptier_ , _duller_ , more _alienated_ , more _inhuman_. Not when he first willed his primary school classmates to stop levitating after they stole his money; not when he learned what those ugly little letters _Mudblood_ etched onto his notebook meant; not when he laid in the hospital wing after being thrashed by that troll with the deafening knowledge that he had slaughtered it in blind desperation. He was _strong_ …but at what cost? "Are you sure you can handle it?" He had wished someone asked him the very same years back.

Genos, however, wasn't the type to be swayed so easily. "I will undertake any task you assign me, Mister Saitama. Allow me to prove my worth as your disciple!"

"Win the Tournament." The younger stiffened immediately, a wide-eyed, baffled gaze upon the older student. "You've been given a great honor to represent and defend your school. Not only that, but you also have the opportunity to exhibit your skills and test your ingenuity." Sharp and stern, a figure of refined strength and great wisdom. Eyes calculating and focused, he appraised his ' _disciple_.' "You participated well in the first challenge but you allowed Beauxbaton to take the lead."

Genos gulped, embarrassment broiling beneath his skin at the reminder; how could he have let his teacher down already?

Upon witnessing the immediate effects of his words, however, the invented demeanor rapidly fell away as Saitama inelegantly expressed: "But uh…thanks for 'rescuing' me from the sphinx."

As Genos recalled the events, a shadow cast over his face, eyes glinting dangerously with bottled wrath as a memory of a certain wizard resurfaced. "I would have reached you sooner had that _idiot_ not gotten in the way."

Saitama frowned. "Still doesn't give you the right to burn off a chunk of his hair, man." Genos was lucky he wasn't harshly penalized for bad sportsmanship. In Pani— _Sonic's_ defense, he had gotten a bit confused as to why two of his 'friends' were hogtied and shoved in a sarcophagus. Accepting the quiet, 'Duly noted,' from the other, Saitama continued. "Anyways, yeah. Win. Do it for the experience, the glory, whatever motivation you have." He turned to him, eyes slanted dangerously. "I wanna see what you've got."

"Yes, sir!" Genos looked up, a determination emanating from him like wildfire. "I will succeed—for you, Mister Saitama!"

Said motivation groaned. " _Don't call me that!_ "

* * *

This was very obviously the work of a warped crone up there, cackling in the high heavens at Saitama's misfortune as she twisted her wheel of fate clockwise and counter.

Damn. He really had his money on Beauxbaton.

Fucking Panic was a letdown too.

Don't get him wrong—he knew very well Genos was tough. He thought it would at least be a close match. He just didn't count on the kid having _alchemic enhancements_ on his arms. The fire-show was pretty enough at least as Saitama watched his plans go up in smoke when Genos emerged from the _Shadow Cast_ with the Triwizard Cup in his rune-inscripted hands, gold eyes beaming up at Saitama.

"You're my teacher now," was the slightly breathless and all-too happy greeting Saitama received as Genos parted crowds to reach the seventh year Hufflepuff in the Great Hall.

Saitama gave a wry smile. "That I am. Good job, Genos." Saitama honestly didn't know what to make of the starry-eyed look the kid gave him—other than to suck it up and go through with his part of the deal. Well, he needed a job anyways, right? "But uh…explain to me…how this is going to work? What with you living off in…wherever Durmstrang is."

"Ah, yes. I've thought about that." Saitama was not at all surprised. "For this summer, I'd like to spend some time with you." Genos's face reddened lightly; it must've been all the excitement and festivity from his victory, the elder mused. "I'd like to get started on training as soon as possible."

Saitama blinked. "All right…?"

"And…for the upcoming school year," There was the slightest pause, as though the younger wizard had to collect his thoughts (and courage) for a split second before firmly asserting: "I'd like you to move in with me at the Durmstrang Institute. I've requested special permission from my headmaster and while the decision is still pending, I'm sure they'll consider the circumstances and bend to my persuasion."

"Yeah, no," Saitama replied flatly. "Absolutely not. I told you that before, didn't I?"

At that, Genos dropped a rather large and weighty cloth pouch in Saitama's hands, eyes blazing with tenacity. "I'll pay you."

And even though Saitama very well knew what was inside, he peeked anyways. Yep. Those were a _lot_ of Galleons. Well…only one thing to say to that: "Remind me to pack my toothbrush."

Observing the scene from a not-so-far-off distance, King grabbed a certain Gryffindor by the arm and hissed, "I can't believe this—I can't believe _you_!" The larger man gestured wildly at the scene before them, concern more than evident. "You basically married off our friend, Mumen!"

"He was just asking so many questions! I just wanted more people to know how good a guy Saitama is! I didn't know he'd use it for this!" the prefect defended. When King still looked highly unconvinced, Mumen gave a soft noise of guilt. Still, as he looked over to the pair, he figured that things couldn't have turned out that badly for Saitama. "Well…they look rather happy, at least?"

… _Right_?

Well, at least one of them did. "Thank you, Mister Saitama! I'll be sure to do so," Genos beamed, looking for all the world like he had just been awarded the Triwizard Cup—which he _did_ , but he certainly didn't look like that during the ceremony not too long ago. Or maybe he looked like a little kid who had just been promised a new puppy.

"Uhuh…" Said leashed-puppy replied, mechanically nodding, eyes devoid of any intelligible emotion.

"See? Even Saitama's smiling!" Mumen whispered with a triumphant grin.

King shook his head. "Mumen, that is the look of a man internally screaming at himself over poor life choices."

And indeed, King was correct. As Genos was (regretfully) swept off by a crowd of cheering peers and professors, Saitama made his way to his two friends and wobbly sat down, head in his palms as he rested his elbows on the table. There might've been two tentative hands patting his back in sympathy but he wasn't minding that right now. He had more pressing matters to attend to. Like…

How the hell was he going to explain to Genos that the secret to his strength _really_ was _all in the wrist?!_

* * *

Notes:

I probably got a thousand small details wrong but I tried! ((It has been years since I picked up a Harry Potter novel.))

* = in reference to when Genos bought Saitama a whole box of a hard-to-find drink Saitama was craving.

Also, I think Genos should have been shorter than he was described since it was mentioned that he was a tiny kid before becoming a cyborg, but I'll just chalk that up to him getting his alchemic enhancements at an earlier age.

Shadow Cast was a reference from a Shadow Mission, "Shadow Cast City," within the MMORPG Mabinogi. The "boss" of this mission is a doppelganger.

Also, yes, I know Durmstrang doesn't allow muggle-born students, but hey—it doesn't seem to affect students' views of them (ex: Viktor Krum). Genos will probably have to jump through a lot of hoops to smuggle Saitama into Durmstrang though.

This fic has a strange timeline; it's semi-modern day (ish?) because the last Triwizard Tournament before Goblet of Fire was in the late 1700s. And before GoF, there were no age restrictions (?); the restrictions were placed to make the tournament safer as the competition had a rather high mortality rate. So Genos's age isn't a factor—but at the same time, this fic doesn't take place in the 1700s or before. It's an Alternate Universe so perhaps this is in the distant future where the Tournament was brought back without age restrictions due to better repercussions taken to ensure safety.


	6. 5 Punch: Reversal

**5 Punch:** _Reversal_ (or an AU where Genos is the 25 y.o. Hero alongside his reluctant Disciple, 19 y.o. Saitama; Saitama is still OP but Genos has absolutely no idea)

* * *

It was a strange oblivion he teetered on. A mind wrapped in blankness, so barren that Genos wasn't even sure the lightlessness could be called _black_. Complete disconnect from all outside stimuli, a feeling so alien and unnatural that Genos wasn't entirely sure he was even still conscious. It was suffocating, almost, if he had lungs to breathe and a heart that raced as eternity crept upon him, inertia of time nonexistent in the silence that stretched on for a whole, lonely universe within his thoughts and not-thoughts.

Something broke through after a small infinity passed.

 _Sounds_.

Muffled and blaring all at once, shattering the void and quiet as his mind processed the influx of tone, pitch, and intensity—patching the fragments together.

" _Sai_ … _Sai_ —tama-kun?" That was his voice, he weakly recognized. Ragged, broken, buzzing with static— _his_.

"Oh, hey, you're awake!" Another voice.

Warm. Welcoming.

 _Weary._

"It…appears so…" He regained sight next. His scanners were malfunctioning but he had basic visuals, optics taking in the flash of colors glaring at him so loudly. Rubble littered the streets and among them, pieces of himself spilled on the earth. His student leaned over him tentatively, mop of dark hair, apathetic face, ruined tracksuit and all. "What happened?" he heard himself grit out.

"Oh…" Another blank look. One that he had memorized after a span of hours, days, and weeks. "You got knocked out after the Sea King spat some kind of acid on you." An expression he still couldn't decipher. "You're in really bad shape, Genos. I'll get you to the Doctor." An expression that closed protectively over his young disciple.

Walls too high for any to scale. "Is…is the Sea King gone?" No, that was a foolish question. He wouldn't be here right now if the threat wasn't dispatched. "Are the citizens okay?" he tried again his actions betraying him; the remains of his cameras were searching the younger's face, scanners failing to open properly as the execution was met with _Error_ s. _Are you okay?_

"…Yeah." A wan ( _empty_ ) smile. "You and the other heroes really wore him down. I really didn't have to do much—"

"You fought him?" Saitama flinched at that but not even the minor gesture of guilt could derail the thoughts of panic coursing through him at the thought of his young student charging towards a _deadly_ opponent without Genos to guard him. The thought itself made something in his core pulse painfully in his chest, all-too chilling possibilities slicing through his thoughts. "Saitama-kun, I told you—a demon-level threat is still too dangerous—!"

"I know, I know. You've said that." Softly, chiding almost. "You say a lot of things…but I'm okay, so don't worry, all right?" Something cresting the surface, voice spilling to the open air with the smallest trembles. "I'm okay because you and the other heroes did your best. I'm _okay_ , Genos," he quietly ( _desperately_ ) assured. The unspoken _But you aren't_ hung between them like storm clouds awaiting rainfall.

Genos was quiet for a second before trying a chuckle. "Are you ever going to call me ' _Sensei_ '?" It sounded disjointed and frightening.

It was a good thing his disciple didn't scare easily. "Ah, back to that again? I told you, calling you that just sounds weird!"

Genos doesn't know how Saitama could so easily fall back into the strange normalcy built between them. Doesn't know how the teen manages to escape every fight virtually unscathed after Genos's all-too brittle body shuts down. Doesn't know how Saitama could still follow him around, half-heartedly taking note of what Genos offers him—hardly pearls of wisdom but accepted to be truths the teen should follow. Doesn't know how Saitama acknowledges Genos as his teacher, an unspoken acceptance after weeks of reluctance and youthful stubbornness, and yet never intentionally utters the title.

Maybe he will once Genos lives up to it.

And as something in him breaks and crashes all at once, a deafening thought played like a broken record:

 _I can't…I can't believe I let him down again…_

.

.

.:.:.

.: _Fateful Encounter_ : _._

 _"_ _A WEAK PUNCH LIKE THAT WON'T EVEN KILL A MOSQUITO!"_ The monster has him, on the wing as she continues her (rather grating) ridicule. _"HAHAHAHA, HOW WEAK AND FRAGILE YOU ARE!"_

In retrospect, it was partly Genos's fault.

 _I see. The more blood she consumes… the more powerful she gets. I let my guard down and now I have no chance of winning…other than taking her down with me._

What a disappointing way to die. Nevertheless, his core glowed and hummed, a live bomb ticking away in his chest where a heartbeat should have resonated. There might've been a cruel metaphor in that, but he doubted the Doctor would have deliberately crafted such a tragic prophecy.

 _I'm sorry, Doctor…_

Fate was funny, in a malicious way. At least, sometimes. He could spend hours lamenting it, but he really didn't have kind of luxury. However, one second as he was staring death in the face, the next moment his face met concrete as the chatty bug _dropped him_.

A deafening crash followed. Ah. Figures. Fate thought it was hilarious, apparently.

"Man, I _hate_ mosquitoes." A grumble. Irritated and human.

Genos struggled to turn himself over, succeeding after a second or five. "Who are…what ha—" His voice locked in his throat, only two thoughts registering in his mind: _Did he just save me…?_ And _Why is he naked?_

A shadow of recognition fell over the other's expression before erupting into fury. "You…you're that guy! HEY, YOU—YOU DESTROYED MY APARTMENT WHEN— hey…wait, are you okay?"

Genos almost chuckled at the sudden reversal of behavior; or would have had he not just spat out a cloud of smoke as something very important was apparently crushed and needed to reroute the pressure. "Suffered…massive damage…I'm…"

"Hey, hey wait! Don't go dying on me!" Worry. That was strange.

" _Not_ —dying," He reassured, not knowing why he was doing so in the first place. "I will h- _have_ to be—repaired by the Doctor—" He was beginning to lose visuals, scanners closing and a timer going off insisting that his systems reboot. And before it went dark, his eyes found another pair, concern and confusion upon them. Genos barely managed to voice out: "Who are you?"

Auditory was always the last to go, it seemed. "Saitama," the other said. Genos tried repeating it, forming the words on his tongue and tasting the texture. He found he could no longer do so. A spike of panic shot through him. "You should rest. The threat's gone so you can relax for a bit until your Doctor gets here." _Let it be soon, let it be soon_ , but even hoping could only do so much as the world grew smaller and smaller and the emptiness started swallowing him whole. "I'll be here for a while anyways. Don't worry."

" _S-Saitama_ …" The name only echoed in his thoughts.

.:.:…..:.:.

A sterile environment, clinical fluorescent lights and the hum of machinery.

The lab.

"Ah, you're awake!" Another voice; elderly, expectant.

"Doctor Kuseno…" He sat up, mentally assessing the new body; it 'fit' similarly to his last which came as a relief. New skin to the same name. "What happened—"

"What _happened_ was that you were too careless again," the Doctor very nearly snapped. "Honestly, Genos…"

"—to that boy?" he finished. The Doctor paused, raising a brow as Genos clarified: "Saitama."

The scientist sighed. "If you're referring to the young man I found questionably naked right next to your unconscious body, then he's fine." Genos might have been giving him a bland look but the whirring in his chest might just indicate otherwise of the situation. The Doctor raised a brow at the strange occurrence but let it drop for now. "He's sleeping in the other room. I've lent him some of your old clothes to wear in the meantime."

That brought Genos to full attention. "You brought him here? To the lab?" He wasn't worried but he hadn't been expecting that. Allowing an outsider to a secret location that had remained hidden for more than ten years sort of defeated the purpose of having it secret in the first place.

"Yes. But what choice did I have, Genos?" The Doctor sat down on his chair and motioned for him to lay back on the operating table. "In the wake of your rash choices, you've left him without a home—and without anything to wear." The Doctor tsk'd when Genos immediately shot back up. Guilt, dark and consuming, echoed in his mechanical movements where his human features betrayed nothing. "But…you did save him," the Doctor quietly finished.

There was that.

There was that and Genos should never lose sight of it.

Small and quiet. "I did?" Hesitant and dubious. To Genos, it was strange; that didn't seem right; like forcing two pieces together that couldn't lock in place. The other way around, however…

The Doctor hummed before performing another array of tests. "Yes. He told me so himself."

The other way around seemed to fit much better.

.: _Begin_ :.

"Uh…you really didn't have to do all this." A mop of spiky black hair peeked out from the piles of boxes lithe arms carried.

Genos shook his head, opening the apartment door and stepping aside to let the younger in first. "Please allow me to do this, Saitama-kun."

He set the boxes down, brown eyes taking in the spacious room. Excitement thrummed through him but the wariness of the situation overrode the feeling. "But paying for a new apartment? Isn't that a bit much?" He tried not to be awed by the view from the glass window leading to the balcony. Trying, and much to Genos's amusement, failing. But as a brand new sweater spilled from the top of one of the containers, the caution was back in an instant. "And uh…not to mention—"

"Please, _don't_ mention it," Genos insisted as he carried in a new table from the hallway and set it in the middle of the room.

Turning to him, skepticism still written across his face, the younger sighed in relent. " _All_ _right_ …geez, what do you do for a living anyways?" He gestured to the pricy apartment and the new furniture, more than just a bit flustered at the generous treatment.

"I am a cyborg of justice." At that, the suspicion melted away to bewilderment. "An S-rank hero," Genos clarified.

"Woah…seriously?" There was a look of awe on his face that Genos couldn't help but find charming. "A hero? That's so cool! You must've fought off a lot of monsters and bad guys." Charming in the most childish of ways, but it still made the currents of electricity running beneath his synthetic cheeks spark beneath his skin.

"I…have." At the widening smile, Genos felt his own lips mimic the gesture. "Are you…interested in heroes, Saitama-kun?"

.: _Preparations_ :.

"You're awfully concerned about him."

Genos didn't even look up from his computer. "Doctor, I've left him _homeless_ —"

"I saw you searching for apartments the other day. And not ones from Z-City." No, no they weren't; they were around S-City, T-City, and M-City—the closest three in proximity to the lab. "And I've seen you taking his measurements." Again, Genos had nothing to say. "I _know_ for a fact that it isn't because you're stingy about letting someone borrow your clothes."

His clothes barely fit him anyways. Saitama was more towards the slender side despite having a build of lean muscles on his growing body. The sleeveless tees Genos wore were embarrassingly baggy on the teen (he had personally expressed so with a chagrined look) but he wasn't complaining too much given his circumstance. But with Genos's mechanical body, even clothes from years ago were still too large for him.

 _Maybe some clothes from when I was last—_

But those were dark thoughts to dark roads he was traversing on. Besides, back then, he was such a pipsqueak that there was no way a nineteen year old boy could squeeze into his older clothes.

Genos closed his eyes and willed the thoughts away, though they snaked around his conscious, hissing venomously. He never regretted his decision to trade his human flesh for metal armor, his blood and bone for fire and lightning that he called with a simple command. He couldn't. In his actions, he had to be one hundred percent sure. Regret was something he could no longer afford.

The Doctor sent him a worried look at his silence and somber mood. Those looks had been increasing for the past ten years now.

 _Ten years…_

Ten years and he still hadn't reached his goal—his vengeance. And as the sands of time slowly slipped through his fingers, he wondered if he would ever reach his endgame against the mad cyborg. The mad cyborg that stole everything before him—his family, his future—

And inadvertently, perhaps his humanity. A fruitless pursuit that only left him with shiny new bodies to bear and break as though his sense of justice was a mere program downloaded to his core. Blindly chasing shadows of his past, unaware of the damage he had done to himself—

And others.

"It wasn't as though you robbed him of his life, Genos." He stilled. "You are _not_ becoming what you've sworn to take vengeance upon."

 _Is that what the mad cyborg did, Doctor? Rob me of my life?_

 _That's right…I'm barely human anymore…_

 _But, even then…_

Genos shook his head. "No, that's not why."

If the Doctor was surprised, he didn't show it. Silence followed in his wake as he left Genos to his own devices, allowing the cyborg's memories to flood the noiseless room.

 _"_ _You should rest."_

Strange. Why would a machine need to?

A fragile being of bone and flesh,

 _"_ _I'll be here for a while anyways."_

Guarding over a fragmented puzzle of metal and wires,

 _"_ _Don't worry."_

Human eyes reaching out to a human soul.

.: _Begin Again_ :.

"Oh, yeah—well…It's always been a dream of mine," Saitama started, demeanor sheepish as he scratched the back of his head. "As a kid, you know?" No. Genos wouldn't have known. It had been too long since he had anything but his goal, too long since he dreamed of things other than mangled bodies and fire. Of red and revenge. "I've started training up to become one for a few years now."

But Genos knew ambition. Perhaps he and Saitama were the same in that respect. "So, you want to be a hero?"

The younger shrugged. "Well yeah. For a hobby, I guess." And perhaps not.

Golden eyes narrowed at the slight boy before him, unruly mop of black strands and eyes that belied a hollowness one would associate more with a middle-aged man undergoing a midlife crisis rather than a teenager at the cusp of adulthood. But still…the boy had potential. He had, apparently, survived Genos's Incineration and somehow, someway lent a hand in defeating Mosquito Girl though the exact details of both were unknown. And as far as Genos saw, the boy had no one else to turn to. "I see…to undertake such a goal, you need proper guidance. Very well…I accept responsibility."

Saitama frowned, eyebrows bunching together in puzzlement and panic. "Eh? That's not really nece—"

"Do not worry; it's of no burden to me." In retrospect, it would be but Genos wasn't about to allow the young man before him to dashing off into danger untrained and unguided. "It is the least I can do after the damage that befell your apartment. And from now on, please refer to me as 'Sensei.'"

 ** _"_** ** _Weren't you just listening?!"_**

.: _Shift_ :.

 _"_ _THEN WE DON'T NEED THE ONE ON THE LEFT, DO WE?"_

Pain followed. And lots of it. Darkness, as usual, trailed after it.

And as usual, the last of his functions to shut down were his auditory receptors. A fuzzy, " _You'll pay for turning Genos into modern art! Lead the way!_ " haunted his thoughts to search for some kind of meaning in the string of words until the black tide of insentience swept over him.

When he came-to, Saitama had been both relieved that Genos had managed to open his eyes and saddened about missing a Saturday sale. The latter particularly. So much so that instead of " _Where is Carnage Kabuto? What happened to the House of Evolution_ " coming out of his mouth, he instead blurted: "The store is four hours away. If we hurry, we can make it."

His disciple lighting up the way he did ( _was_ _Saitama-kun seven or seventy?_ ) affirmed that Genos made the right choice.

.: _Introductory Course_ :.

"Ah? So there's a whole association of heroes?" Saitama's words were finally becoming intelligible as Genos hurriedly wiped off the gum encasing most of his face. The teen was lucky none of it got on his hair; that would have been a mess. "Huh…I had no idea…" he muttered as he picked off the remaining splotches of sticky sweetness.

Genos honestly worried about him sometimes. "Yes…to become an official hero, you must complete the registration," he explained. "It comprises of a written portion and a physical test."

Bored eyes lit up with an animated gleam. "Oh, that's it? When's the soonest I can join?"

It was so rare that Genos hesitated before giving his honest word. "Perhaps…later. When you're ready."

He pouted for a second before aptly applying that same indifferent mask. "And when will that be?"

Genos sighed. He knew Saitama would be disappointed, but he couldn't allow his disciple to go through with that decision just yet. The teen was still young and very much inexperienced. A few years of training, especially under his regimen, wouldn't save him from the catastrophes and chaos that was inevitable of his line of work. No, he needed to be prepared.

Saitama blinked, cocking his head to the side. "Genos?"

And as his teacher, he would do his absolute best to ready him. "In truth, Saitama-kun…I want you to know what you're getting into when you register as a hero." There was focus in those brown eyes, narrowed and intent. It was an expression Genos had never seen in the teen. It meant that Saitama was _listening_ to him and for the love of god, his voice damn near failed him after he realized it. "It can be a poisonous industry and I want you to be primed when you make the decision to go through with pursuing heroism as your profession."

He had told Saitama the truth—besides his naiveté in the line of duty and danger, there was also the harsh politics involved that Genos feared would turn Saitama away from the purity of his work.

"Poisonous huh…" Saitama hummed, head supported by the arms resting on the table as though skimming the words from Geno's' mouth through his mind. He sat up as he gave his verdict: "Well…that's fine if I wait a bit longer, I guess." He gave a shrug. "I'm only a hero for fun right now anyways."

 _A hero for fun…_

Simple and whole, uncluttered by dangerous ideals that could be easily warped by disenchantment and delusions of grandeur and unfragmented by the views and vices of others that threatened to drive most young minds away from their clear visions of triumph to the vulgar ideals of public eye.

Genos held back a smile. "Right, Saitama-kun."

"And you're still gonna teach me anyways, right?" Genos stilled. "Even if being a hero is more of my hobby." Saitama glanced up at him, their eyes meeting for less than a second before they darted away.

"Yes…Yes I will." Genos didn't hold back this time, giving a small beam at his disciple who was insistently avoiding his gaze. "By the way, since we have this arrangement, I think it's best if I moved in with you." The boy went stock-still as Genos continued. "To ensure you are training diligently and appropriately; this way, you may also learn from your own observations. Not only that, but it is also more economical as you will be coming with me in various missions to gain experience in various lines of hero-work. It also should not be a problem for the landlord—"

It was quite easy to see the rising panic in Saitama's eyes. "Uh… _what_ —"

"—Since I am paying the rent, after all," Genos finished. And just as easy to disregard it. He was pretty sure the look he was giving his student _dared_ him to argue.

It worked too. Whatever Saitama was about to say never surfaced and was swallowed down by a wobbly, "Oh. Right." There was the slightest pause before his student shot him a weary grin. "Remember to pack your toothbrush."

Genos smiled.

.: _Lesson One_ :.

Genos frowned. "Is that really all you do? 100 pushups, 100 sit-ups, 100 squats and a 10 km run?"

"Every day," Saitama added, not a bead of sweat on his brow as he finished up his regimen.

His self-proclaimed teacher blinked. "I see." It…really was a good thing Genos found him after all. With an average regimen such as that, Saitama wouldn't last very long against a real threat.

He was distracted from his thoughts and preliminary analysis of Saitama's physique and prototype proposals to increase the difficulty level of his regime and perhaps plans to ask permission from Doctor Kuseno to simulate some obstacles to add to his student's training when a blaring, " ** _DANGER DETECTED IN M-CITY. DISASTER LEVEL: TIGER_** " severed his tangled thread of thoughts.

They took off without a word.

It wasn't until the sirens repeated for a third time that Saitama broke the silence between them as he looked up at Genos. "You know…I always hear that. Wolf, Tiger, Demon…what do they mean?"

The cyborg blinked, levels of worry for his young student rising just a bit. "You mean you don't know?" What would have happened to him had Genos not found the boy? Contrary to that disturbing thought however, Genos was more than happy to explain. _Then let this be your first official lesson, Saitama-kun._ "They indicate the amount of damage the threat is capable of. A Wolf indicates that their appearance may be a threat. Tiger is a danger to a great number of people. Demon endangers a whole city or its facilities. A Dragon level threat endangers multiple cities. A God level threat endangers survival of humanity in general."

"So a Tiger is a threat to a lot of people hm…" It didn't take him long at all to exclaim, "We should hurry!"

His enthusiasm was a bit baffling. "Yes, we should," Genos agreed. Even as they sped towards the menace (direction made obvious by the countercurrent of people running _away_ from the area), he further explicated, "It should also be noted, however, that most heroes also look at the threat level to decide whether they should move or not."

Saitama made a noise of confusion. "Ah…but that's lame. I mean," he trained his eyes forward, keeping pace with his teacher as an explosion in the distance resonated through the crowded streets. "If the heroes run and hide, who will stay and fight?"

Genos slowed for a fraction of a second, just enough to purely observe the baffled and exasperated expression on his student's face as he navigated through the retreating civilians, not because it was a mess he didn't expect others to handle properly or because he would attain any sort of fame, but for something else entirely.

And suddenly, he turned to him, an unexpectedly bright smile on his face. "Good thing that's not the case with you, Genos."

The first thought that entered his mind upon his student's proclamation was that he should ask the Doctor about that small whirring noise from his core; it started up ever since he was repaired from the House of—no, even before that. Perhaps after the fight with Mosquito Girl.

The second was: _Maybe I'm the one getting a lesson here…_

.: _Everything_ :.

He just _had_ to come back for that damn cactus.

And off all the days, of all the hours, a giant meteor just _had_ to show up the same time his disciple realized he had put his cactus inside the apartment due to the unnaturally heavy rains that week and Genos just _had_ to encourage him by saying his cactus might still be alive in the rubble somewhere. And Saitama just _had_ to give him that childish look of awe and impatience to fetch it that Genos couldn't possibly resist.

Fate was fickle too, he supposed.

As demonstrated by the flaming piece of space-rock hurtling towards the stratosphere and onto a city of panicking citizens and three S-rank heroes. Well two, technically, since one of them was operating from a comfortable distance.

Even then, Metal Knight's impressive barrage did nothing to stop the threat as it loomed over the city. Genos wasn't even sure how much firepower his new arms had. The situation was bleak—or maybe something lower than that.

Maybe _fickle_ wouldn't fit exactly right, but that's what Genos had in his mind.

 _Fickle_ because he was there, upon a ruined rooftop with Silver Fang watching on in quiet support (or was it silent resignation?) and giving it his absolute all, core draining and fire pulsing and surging through his metal bones and copper veins, mind no longer focused on failure and instead on a passing vision of his bored disciple, somewhere in this god-forsaken city that was mere seconds away from turning to dust and debris, fragments of stars and concrete burying their bones.

Indeed, _fate_ was _fickle_ —fickle enough to spare his life and fickle enough to only do so when he sold it for a pitiful purpose that didn't warrant a life at all— _fickle_ enough that in all his time risking himself for humanity, he gave pieces of it away with every upgrade, every _improvement_ that brought him closer to becoming a weapon of destruction than a man seeking retribution— and _fickle_ that he was finally gathering those lost pieces back every time he came home to their apartment, finding the familiar mop of jet black spikes buried in some manga as the news ran on in the background— _fickle_ that he found simple joys again in cooking for another person and sharing simple conversations over dinner and until Genos sent his grumbling student to bed early for proper growth and development— _fickle_ that he took on a student with the hopes of molding a young mind and keeping him on the right path when it turned out that _learning_ and _teaching_ went hand-in-hand and that Genos discovered just as much from a bored teenager who dreamed of becoming a hero for simple enjoyment, a perspective so contrary to his own that Genos came to cherish, just as he learned to cherish the other's faithful presence by his side, his awkward and warped sense of humor, his unique sense of fashion, his inability to come even close to petting a stray cat, and his incapability of separating _anything_ evenly (be it chopsticks or twin popsicles)

—and _fickle_ because as his vision went black and his knees fell to the ground and internal sirens shrieked at him for losing too much energy much too fast, he could only think about how his student came back home last night with a carton of broken eggs with such a sorry look on his face that Genos ended up making eggs over rice to cheer him up—and how _fickle_ was it that his student _finally—finally_ called him " _Sensei_ " so charmingly in gratitude even though it was probably by accident and when asked (teased) about it, Saitama only continued to firmly deny it ever happening.

Fate was fickle for giving him those stolen moments of happiness back and wrenching it away once more.

 _Strange_ —his wasted years and unattained vengeance was definitely the first among his thoughts as the flames sputtered their last and he once again found himself face down on concrete as his remaining senses began to fade.

But his final musings were that he really would have liked to hear Saitama call him "Sensei" out of respect—just _once_ —before his auditory receptors shut down for good.

So much so that he might have deluded the familiar sound of his student's voice calling out, _"Old man, take care of my Sensei, will you?"_

 _Yes. Saitama-kun should definitely call him that more often._

.

.

.:.:.

.: _For Good_ :.

A sterile environment, clinical fluorescent lights and the hum of machinery.

The lab.

"Welcome back, Genos." Patient, paternal; Doctor Kuseno.

He felt groggy, as though he had been casted to sleep for too long. "Doctor…where is Saitama-kun?"

The Doctor didn't look up from where he sat, running a few more scans on Genos's new body. The acid had been a problem. He made sure it wouldn't be again. "Where he usually is: in the spare room. He fell asleep waiting for your repairs."

Eyes fell downcast. "I see…"

"It's a good thing he doesn't insist on staying here for very long," the Doctor started, closing the various programs and analyses, "You tend to talk in your sleep, you know." There was an amused grin at that, one that Genos immediately caught.

He gulped, core whirring. "I…see." That was definitely reason to worry.

He should probably ask the Doctor about the strange noise since he's here. But the man had his own concerns as he stood and gave Genos a reprimanding look. "While I am glad that Saitama-kun is having such a positive impact on your social health…" he sighed, aged and weary and Genos couldn't help but feel guilty. "Please, try to understand that it doesn't mean you should hurl yourself into peril just to meet his expectations."

"That's not it—I," and it's not, it's _really_ not. It was never about being the perfect teacher, being the _better_ one between the two. It wasn't and that fact _scared_ him all the more. "I want to make sure he's safe," Genos shakily revealed as those muted nightmares and the everyday worst-case-scenarios he had tucked away into the dark started resurfacing. "He's young, and naïve at times, and he only listens to half the things I say, he's too impatient and he just slips out of my sight the moment I'm distracted and…"

It's ridiculous because it wasn't _Saitama_ whose body ended up on the operating table, wasn't _Saitama_ who dealt with the brink of _death_ during the most dire moments, wasn't _Saitama_ in the midst of jeopardy that came all too often with the glittering and gilded title of " _Hero."_

And as long as Genos was there, he'd make sure it would _never_ be Saitama who suffered. "He's too ambitious. Too hopeful. Too—"

"Human?" Genos stilled as the word reverberated in the near-silence. "As are you, though you seem to forget," the Doctor noted. There was another unsteady breath, far too tired and far too distraught. "He worries for you, you know. He usually just goes straight to the other room to wait, but this time…this time he just stood there, watching as I deconstructed your body, wire by wire, bolt by bolt. The only thing he said to me that whole time was ' _Is he hurt?_ ' And I told him ' _No, he's just sleeping right now._ ' He looked so— _relieved_ and it _pained_ me to see that kind of expression on him."

It pained Genos too, the Doctor realized.

Rightly so because the cyborg should take that genius brain of his and realize what he had been inadvertently doing. "You're all he has, Genos. I've seen him change too. And if you can't learn to keep yourself from rushing into danger, at least try and have _some_ self-preservation—for _him_. At the very least…you owe Saitama-kun that."

And was that what plagued Saitama's mind? That his idiot teacher seemed far too eager to dash into the lines of destruction and duty? That being a hero somehow meant that it was okay to weigh one life and throw it away for the unguaranteed survival of others? And that _one_ life—even if it were important, _precious_ , to him—was worth the agony and loneliness if it was all in the name of _justice_?

Because it wasn't.

Nothing of _anyone_ was just "throwaway." Neither _life_ , nor _limb_.

And Genos sometimes forgot that metal ones counted too.

He shook his head and offered the best he could give. "I…can only try, Doctor."

The man smiled at him, exhausted but yielding. "That's all I can ask." For now, it would have to be enough. "I'm sure Saitama would appreciate that from the one most important to him."

Genos gave him a small smile though Doctor Kuseno was sure it wasn't entirely for him. The whirring started up again too. The strange phenomenon hadn't escaped the Doctor's attention since it began since it was definitely _strange_. Well…a scientist should experiment, right? "By the way, Genos…you _are_ teaching him to be a hero, right?"

Not only that, but it would get Genos away from those consuming thoughts for a while. "Saitama-kun? Of course!"

"Okay…good…for a moment I had thought the lessons entailed something…ah, never mind that," the Doctor hastily amended. And for a while, it was quiet with an unspoken question hanging in the lab's sterile air before the Doctor cautiously started with testing his hypothesis. Hopefully, Genos and even Saitama-kun would forgive him eventually. "I should have mentioned this earlier, but…Saitama-kun actually left because you started some strange mumblings."

Genos wasn't sure how his core could turn ice-cold like that, very nearly freezing the electrical impulses in his body. "

"About him ' _charmingly'_ calling you ' _Sensei'_ more often."

What Genos _was_ sure about was a fuse blew out somewhere important; he thanked the malicious fates that he couldn't blush but the fact that his fans were working on overdrive to keep him from overheating was hardly compensating. "A-ah, yes, Doctor. About that, I can explain—"

"No need!" the Doctor hastily interjected. "Saitama-kun is nineteen, Genos. A six year difference isn't so bad!"

" _Doctor!_ " It was a good thing he was already in the lab; he needed this damn whirring fixed right away.

Thoroughly embarrassed and awkward as well, the Doctor still couldn't help himself as he happily stated: "Barely legal is still legal, my boy!"

 _"_ _DOCTOR!"_

Yes, it was a very good thing.

* * *

Notes:

I added the last bit because I wanted to end on a happier note. It really wasn't meant to be all-that shippy haha…because somehow, when I want to make a simple-sounding AU, things tend to go everywhere and nowhere very happy.

And I know, some of the timelines are messed up with the order, but it's really not going chronologically—Genos is pretty much just swimming through memory-soup. The starting events with the Sea King are set during the "present" and all were flashbacks up until _For Good_. It's really disjointed but I hope you get the gist of what I'm saying ^^

What happened in _Fateful Encounter_ was that Saitama had been away from his house (most likely buying groceries) when Mosquito Girl and Genos were duking it out; the fight actually took place in the abandoned district right next to Saitama's home. And since…well it was _abandoned_ , Genos decided to incinerate everything in sight when the mosquitoes flooded the streets. Cut to Saitama rushing over to the ominous cloud (of mosquitoes) gathering towards his apartment only to be bombarded with fire courtesy of Genos. Yes, he burned his groceries too.

Cities S, T, and M for STEM (science, technology, engineering, and math) to border a hidden laboratory because why not~

Info about this AU:

Genos always gets knocked out/things prevent him from being able to witness Saitama's awesome OPness and just thinks "Oh god this kid wants to be a hero for fun? WITH THAT TRAINING REGIMEN?" and so he feels the need to protect Saitama and always refers to him as his "disciple" even though Saitama is the one knocking out the bad guys after every fight.

Genos assumes some heroes come and help out when he's not there. Saitama goes along with it.

Saitama doesn't really mind either and he does appreciate Genos trying to take care of him. He just wishes the cyborg would let him fight sooner rather than having his self-proclaimed teacher telling to stay back because it's too dangerous. He slips out sometimes because he doesn't like waiting hahaha

And Saitama is still mostly the same. He started his training regimen at 15 and by 16.5 became super strong. At 19, he's utterly bored. And I'm not sure when he'll lose his hair…

Also, for the OOC-ness, please keep in mind that Saitama is young, though not by much, but it does still have an impact on him and his dynamic with Genos. Also, keep in mind that Genos is older and has been starved of other human contact for much longer than in the original universe. He wants to be a protector-figure for Saitama because he was the first to reach out to him as another human being, not just a hero or machine.


	7. 6 Punch: Missing Pieces

**6 Punch** : _Missing Pieces_ (or Genos recruits the help of his friends to find something very important)

* * *

It was completely inevitable.

Just as there were many in this life: dusk shifting to dawn, the turning of the seasons, the progression of time from shine to rust, from bones to dust, the dangers and demands that came with adorning the title and mantle _Hero_ —

His marriage was one of the happier ones Genos could list.

If only to make himself feel better about this entire situation.

Because Genos was a hero and heroes had difficult jobs that ranged from saving an entire town from a falling meteor, preserving the lives of citizens from a mutated sea creature, and fighting off a literal _Dragon_ level threat.

And yes, he meant an actual, factual, fire-breathing reptile that some offshore oil company had disturbed from the depths of slumber beneath the waves. It had proclaimed itself (in suspiciously perfect modern tongue) to be named _Seadragonus Giganticus Maximus*_ and it would have said more but no one was very eager to hear a thousand-year-old introduction.

That was fine; the Dragon itself wasn't too patient dealing with them either.

Which was how Genos found himself among the last heroes standing and ten minutes late for dinner. Oh well, that at least means his Sensei would come looking for him eventually—if the news reports hadn't attempted to cover the story yet.

He had been wounded heavily (as far as metal parts went), fans keeping him from overheating as the area around him was ravaged by dragon-fire, flames licking at the earth and scorching it like scars. The damage was extensive but he would fight as long as he was able to keep the people safe.

He held his hand over his chest, fingertips grazing a singular reminder.

And…he'd keep himself safe too.

Easier promised than done however, as the scaly thing threw another nasty fit at a newcomer.

A dragon's tantrum, apparently, translates to earthshattering quakes and a flurry of fire. Inevitability played a role in this, as usual _._ Inevitability at its finest as the Genos caught himself in the midst of it all. Inevitable because it had been a record-breaking _nine months_ since his last full-body repair and, though Genos wasn't a superstitious man, he just _knew_ something would come along and shatter his impressive streak sooner or later because it just seemed like the universe's running gag to send him back to Doctor Kuseno's lab in pieces.

Inevitable too, in that as his vision went white at the unwanted embrace of flames and pain injected into his wires and coursed through his body where blood should have flowed, the last thought that processed through his brain—immediately after _Oh shit_ —was:

 _Sensei will be_ so _disappointed._

* * *

Nine months took a toll on him.

The grogginess was something that took a while to get used to; back then, he was in no short supply of experience. This time however…

"Ah. It certainly has been a while, hasn't it Genos?" The warm voice calmed the furious spinning in his head at the very least. "Back at the operating table, I mean." Yes it certainly had been but it would have been nicer to catch up over lunch rather than the fairly morbid sessions they shared when the Doctor repaired his parts or transplanted him to another body altogether.

"I'm sorry, Doctor…" he mumbled, knowing that he was apologizing for much more than mere inconvenience.

The Doctor shook his head, paternal fondness apparent. "No need to be, my boy. Again, it's been a while." He stood from his seat and gave a brief visual inspection of the new body as he carried on with a light tone. "And it's good that you've been more careful! But some things are simply inevitable."

Genos winced. "Right," he sighed. And maybe it was inevitable—like summer storms and autumn fog. A force of nature like an unshakeable entropy that demanded metal limbs in exchange for the safety of flesh and bone.

 _That_ kind of inevitable.

Or inevitable like waking up with the agonizing realization that the person most important to you was also the person who you thought could never return your feelings—only to be proven completely, foolishly, and wonderfully wrong. Or something tiny, like the wayward flight of an insect to a balcony one afternoon, a meeting of two people orchestrated by the most haphazard of happenstances.

(That _too_ was inevitability.)

It was funny how his thoughts came to the same thing over and over again. Call it the "honeymoon phase," but Genos had been this way since his beloved Sensei said _okay_ in pursuing a relationship with him, _of course_ when Genos first asked him if they were in love, _yes_ when Genos proposed, and _I do_ when he took his hand, to have and to hold.

What _wasn't_ funny was impulsively reaching for the small compartment and realizing nothing was there. "Ah?!"

The Doctor made a noise of curiosity as he looked up from the computer screen. "What is it, Genos?"

He immediately sat up, a cold dread coming over him. "Doctor—have you seen my—"

Seeing where his hand was resting, the Doctor's eyes widened with worry. "Oh? No…no I haven't…" He gave a troubled look and the first instinct Genos had was to immediately panic. "I don't recall seeing it when you were brought here—wait just a moment, let me find your old parts—"

"I'll help you look!" Genos insisted as he hurriedly trailed after the Doctor to sift through the debris.

* * *

Impossible. This was—

 _Impossible_.

"Ah…I'm deeply sorry, my boy," Doctor Kuseno murmured as he patted the cyborg's metal back. "It must be where you last— _Genos_ , what's wrong?"

His voice was so small the Doctor had to lean in to hear properly. "S- _Saitama_ …" The Doctor's eyes widened. _Oh no_. Genos used his Sensei's actual name. "H- _he…_ "

"W-wait, Genos!" the Doctor panicked. "Don't worry! I'm sure it'll be fine!" he consoled as gold and black eyes glistened and a protruding lower lip started to wobble.

Good lord. Why did he think making the boy cry _oil_ was a good idea?

* * *

 _"_ _That cost a shitton of money—so you better as hell take care of it, you hear me?"_

In retrospect, the threat would have sounded much more like one if his beloved's head wasn't currently buried in his metal chest. The red-tipped ears, however, was a clear indication of third-degree embarrassment.

Cupping the other's face and bringing him to meet his eyes, Genos chuckled at the endearing sight: flushed cheeks, furrowed brows, pinked lips from nervous nibbling, and enraged eyes at being caught with such a vulnerable expression.

Genos felt like his core could burst (but thankfully, Doctor Kuseno took care of that little problem after the last time).

And what could he do but lean down for a kiss?

Slow and sweet, passing along a whispered secret that only lovers knew; head dizzy with delight and the phantom of a beating organ running and tripping in triple time as Saitama tilted his head _just so_ to deepen the intimacy between them until the space apart was atom-tiny, the small moment of utter _happiness_ somehow impossible (but he'd be proven wrong time and time again), wonderful (almost unbearably so) and _everything_ all at once—the oxygen Genos would never again live without.

He pulled away, just a breath's distance. " _Yes…the answer is yes."_

Saitama gave him a shaky smile, one that tested how much the Doctor's new cooling systems could really handle. _"I thought that was my line. You asked first, remember?"_ He pressed a soft kiss on Genos's beaming mouth. Halfheartedly (and half-nervously) he added, _"And you better not say 'I do' either—because that's next month and—"_

 _"_ _It's 'yes.' 'Yes,' every time."_ Genos kissed Saitama again before his fiancé found him far too embarrassing to even look at. _"And every day for the rest of our lives."_

* * *

He wouldn't live to see the next day.

Not if his husband found out about this.

He had to act fast if he wanted his marital bliss (and lifespan) to last more than an embarrassingly few number of months.

Of course, he couldn't possibly do it alone.

"I'm glad you all came at such short notice," Genos greeted, approaching the band of free laborers he gathered for his purpose. Impromptu but necessary.

"Whatever. You better make this quick, you hear me?" He felt his eye twitch. Was it really necessary for him to ask the shitty br— _Tatsumaki_ for help? The answer was felt in the empty compartment of his jugular notch. Yes, it really was.

"It's certainly unusual for you to call on us," Bang commented, toeing a scorched piece of rubble from the ground. The elder man frowned as it dirtied his shoe.

"Especially without Saitama," Fubuki added, arms crossed as she raised a brow at the cyborg.

King cleared his throat, trying not to appear too nervous among the other heroes. "Where is he anyways? It's actually pretty rare to see you two without each other nowadays." Genos eyed him critically upon voicing the question, hearing the man's roaring engine as their eyes met. Genos glanced away; it wouldn't do to challenge him when he needed his help. It had been rather difficult to get him to come along, especially without Saitama's presence (and without Saitama's knowing) but in the end, Genos's grave persuasion won him out.

None were so difficult than Mumen Rider, however. "It seems like a serious matter…should we find him?" the C-Class hero offered, having just finished his patrols around the area.

At that, something akin to a trigger set off an alarm in Genos's mind. " ** _Sensei cannot know about this! Absolutely not!"_**

A suspicious silence followed. Had they not been proper adults about the situation, they would have started murmuring amongst themselves at the rather eccentric (more so than usual) behavior Genos was displaying.

Thankfully, among them as _not_ an adult. "…why?" Dōtei asked, not at all pleased he had been dragged out of his lab upon the urgent request from a fellow S-Class hero.

After gathering himself for a moment, Genos turned to them, face uncharacteristically expressive and unnervingly miserable. "Because…I'm here to ask you all…to help me look for my wedding ring."

After a beat of silence, there was a chorused, " _Ah_."

That explained everything.

* * *

A slab of concrete was lifted from the ground, critically examined, and when deemed free of any glittering or gleaming substance, was promptly tossed into the air to land several yards away. "Stupid piece of junk…I have better use of my time," the elder ESPer audibly grumbled.

"Yet here you are with us…looking for a wedding band of all things," Fubuki muttered beneath her breath as she raised a string of debris and manually scanned them. "In this _wreckage_ ," she finished with a frustrated groan, tossing the rubble away in a pile.

It had been over and hour and they were barely making any progress.

Though defeated by what the news reports claimed as "an unseen force of sheer destructive energy blasting a hole right through the creature," the dragon definitely left its mark. The damage ran on for miles and in the aftermath, it was difficult to gauge where Genos had been during the fight.

Sitting up from his crouched position, Bang gave a groan before standing to approach the youngest S-Class hero and another potential search-space. "Dōtei…I didn't want to ask this in front of Genos earlier, but…what are the odds of the ring being destroyed after Genos was hit?" Bang inquired as he hefted the remains of a building out of the way to inspect the underside for anything that shone in the sunlight.

"Significantly high," the child prodigy replied with a frown as he looked up from his own radars.

There was a cacophony of _"What?"_ and various clutters and crashes that followed upon the dismal prognosis.

Dōtei continued, unperturbed. "Well, if it was an ordinary gold band like it appeared, it could have melted. Gold's soft and malleable, lending to its popularity with jewelry, but it has a higher melting point compared to some other metals due to how its atoms are loosely arranged. Even then, though gold can't melt with ordinary fires, that creature's flames were hot enough to melt Genos's titanium alloy limbs and plates after one of its blasts." The boy typed away at the protruding device from his backpack, screen pulsing with faint blips throughout the displayed grid. "Not to mention the earthquakes it caused; it could have just as easily fallen out and gotten crushed under dropping wreckage or slipped into the cracks beneath after they occurred, destroying it or making it nearly impossible to find." He sighed as he closed the program. "I had hoped that the damage to the battleground wasn't as great as I had predicted, but with everything either in pieces or in ashes, we're not exactly in the ideal conditions to go looking for a ring that could have been charred black or melted to veins."

There were discreet glances at one another, incredulous, devastated, and sympathetic.

Mumen brightened however as a thought occurred to him. "Ah, but Genos keeps it in that special compartment in his chest—"

 _"—_ _That was probably also destroyed,_ " Dōtei interjected.

"Fair point," he replied with a frown.

"Then what are we doing here?" Tastumaki demanded, a wave of psychic energy vibrating frighteningly about her. "If it's likely destroyed, then what's the use? We might as well—"

A detonation sounded off in the distance, a cloud of dirt and debris flying and falling; as the air began to clear, a silhouette started to form. Genos was revealed in the haze's wake, standing over the remains of a ruined structure before giving a frustrated kick and watching it crumble to dust. With startling resignation, he began to sift through where it once stood, a picture of diligence, devotion (and perhaps, delusion).

The younger sister shook her head. "I wouldn't, sis," Fubuki chided gently before she turned back to another square of toppled buildings and mounds of rubble. "He needs our help. C'mon."

"Tch…" the elder ESPer grumbled; even then, her harsh gaze softened ever-so-slightly, her lips twisting to a small frown. " _Fine_. I'll…look some more over here…" She floated off to another sector, carefully removing fragments of buildings and streets jutting from the ruined ground, green eyes searching meticulously.

Bang looked on worriedly as the solemn cyborg continued to sort through the refuse. "I'll assist Genos in the meantime; maybe two heads will be better than one," he reasoned as he walked over to him.

Dōtei nodded wordlessly, resuming his task as the spiderlike limbs of his engineering genius migrated him over to an adjacent knoll of asphalt and brick.

And witnessing all this, Mumen couldn't help but sigh in wonder. "Is…Saitama really _that_ scary when he's mad?" It was hard to imagine Genos of all people _fearing_ the easygoing hero.

Beside him, King snorted. "Honestly? _Yeah_." There was a reason why King doesn't play Super Smash Bros. with Saitama (anymore). Still, the man shrugged as he stooped down, manually digging through the remaining pile of junk and dirt that littered the area. "But…that's not the reason why Genos is so worried."

And looking over at the cyborg now, it wasn't hard to realize that as they watched him give a single nod and wordlessly accepted Bang's aid, moving over for the elder as they sieved and searched the scorched earth for the tiniest glimmer of light.

Mumen squatted down as he got to work once more, helping King with another pile of ash and dirt nearby.

They knew what they were doing this for— _who_ they were doing this for. For their friend—a man who loved his husband more than anything—and more than anything, would do whatever it took to protect any part of the strongest man any of them knew. The ring Saitama had given him on their wedding day was no exception.

* * *

It took six long hours but they'd _finally_ found it—

—found the guts to tell Genos they couldn't find the ring, that was.

"We've turned over every slab of concrete, asphalt, and even damn pebbles…" Tatsumaki started, arms crossed and a scowl marring her face.

Dōtei shook his head, eyeing the data from his machine. "And I've already scanned the entire area five times…"

Fubuki sighed as she patted down her dress, forming clouds of ash and dirt from the long hours spent searching and scouring. "We've tried our best. Genos, we're _really_ sorry but—"

He raised a metal hand. "It's okay." They stilled at the reply. They crowded around, watching as Genos lowered his eyes to the blackened terrain. "I…understand," he murmured, voice barely above a whisper.

Bang blinked. "Are you…"

Mumen looked concernedly to King. "Is he…"

With that, Genos swiveled around, the smallest of shudders visible as he stalked off in the other direction. "You all can leave. Thank you for y-your help." _Was that_ …"I-I'll just take one last look a-around." A _tremble_ in his voice?

They stood, not daring a word until they heard it:

A quickened intake of breath, involuntary and wet, and the movement a mechanical arm quickly wiping something from his cheek.

Something splintered in all of them.

"Wait—we'll help!" Mumen stumbled, hesitantly darting off to another area he supposed he hadn't checked _that_ thoroughly. King silently followed after him, desperate to go home, but not so desperate that he'd allow Genos to cry.

"I-It's gotta be here somewhere right?" Fubuki stammered, racing off to the opposite direction, psychic energy levitating clusters of concrete.

"Are you doubting me? I never said I couldn't find it—and I told you _I'd findit_!" Tatsumaki yelled, taking to the sky in another corner of the sector, fragments of roads and mangled poles flying in her wake.

"Another look around the perimeter won't hurt," Dōtei grumbled, the mechanical legs of his backpack dragging him to the farthest posts, machines humming madly as he sorted through the different elements, mixtures, and compounds his scanners picked up.

Bang chuckled, placing a comforting hand on a metal shoulder. "Let's have another look around, shall we?" His response came in an enthusiastic nod from a blond head.

And if anyone caught a glimpse of Genos's oil-stained face, no one said a word of it.

Minutes, then hours crept by, toiling away. Against himself, the cyborg smiled, knowing that perhaps it was all fruitless to sieve through the endless sea of charcoal black and ashen grey for that one glimpse of gold. Still, as miserable as Genos was feeling—it was somewhat of a consolation that he had— _friends—_ he realized with a start, warm and freeing—willing to lend a few hands, a highly advanced metal detector, and psychic powers to help him out.

* * *

In the end, it didn't help.

After the sun went down and it became too dark for human eyes to see, they called it quits "for the meantime." The half-smiles said that they'd be willing to try again tomorrow but the sorry glances they sent him when they thought he wasn't looking said that it was hopeless.

In reality, it kind of was.

When the Doctor sorted through his previous body, they found nothing in the small compartment. The tiny cavity had been smashed to pieces, the precious contents inside nowhere to be found. That should have been his first indication.

But he had people to call and numbers to flaunt— however much companies needed to line their pockets to perform thorough searches. But upon uttering the site of excavation, they dropped their negotiations immediately. The damn dragon left its mark on that territory and no corporation was fool enough to disturb the adjacent sea for fear of another outbreak of loose cannon reptiles.

In the end, he only had a select few to depend on but even then it hadn't been enough.

For all the hope he had against all the obstacles he met, it seemed only inevitable that he'd trudge back home, empty handed while his heart ached for its missing piece.

He felt the leaden weight in his chest as he approached his shared home with his Sensei, his Beloved—his _husband_. And the reminder that he had been careless enough to lose the symbol of their union made his core pulse painfully as he turned the knob and opened the door.

He found Saitama's head peeking into the hallway, brightening at the sight of him. "Oh hey, did you—Genos?" His mood immediately shifted to worry at the expression marring the younger's face. "What's wrong?"

It should have been the scene of domestic bliss: his husband, adorning his pink apron and greeting him from the kitchen as the smell of dinner wafted through the apartment, the gleaming gold band on his Beloved's left hand, fourth proximal digit upon the fabled _vena amoris_ , safe, whole, and tenderly placed where it belonged after removing it from the clasp around his neck, hidden beneath the hero uniform he wore on a near-daily basis, defeating dangers that threatened to destroy entire cities and lives, protected in the place that echoed where Genos had stored his own for safekeeping.

 _Had_.

Because Genos couldn't even do that.

"I…" And how was he to face his husband after this? " _I_ …"

"Ah?" Saitama cocked his head to the side, eyes widening after a second or two when he realized what was happening. "Wait, don't cry!" he panicked before dashing to the living room for a few seconds, the cluttering and opening of a drawer heard in the commotion before he bounded to the bathroom. "W-wait here!"

He was probably looking for towels. Great. Just great. He was going to break his darling husband's heart _and_ he was going to stain the floor.

It was pretty pathetic.

Then again, it _really_ was, as he was ushered to the living room, his husband dabbing his eyes periodically while murmuring (what were hopefully) consoling words that Genos couldn't process right away. He was made to sit down with a stern hand on his shoulder. Looking up dejectedly, his visual input lingered long enough to recognize that his Sensei had a towel slung over his shoulder; immediately following that, he tugged the man closer and sighed in a strange emotion betwixt despair and delight as his husband allowed him to wallow and sulk there in his arms.

Genos thrilled (and whimpered a little) as the older man started rubbing small circles on his back. "I don't know what got you down but uh…" the other hand drew away from Genos's waist to dig through his pants pocket, wiggling his hips a bit to take out a small box. "Maybe this will make you feel better?"

Even then, Genos could still feel the cold acceptance creep up on him. He had to tell his husband the truth. No matter how much it hurt either of them. He drew away with a resigned breath, ready to face the worst—be it Saitama's fury or his sorrow. "Sensei, I— _!?_ "

Some things in this world were simply inevitable.

Losing everything he had and trading away what was left of him.

Allowing revenge to drive his life and consume his spirit.

And somehow finding his way again.

By choosing to follow a lone hero, the strongest and kindest he had ever known.

And falling madly, foolishly, fearfully, and absolutely in love with him.

Then learning and knowing every drop of emotion was returned.

And choosing to be with him forever.

Yes, even the small things: like how Saitama opened the small box, took out the gold band inside, and held it out for Genos to see.

And like how Saitama-sensei always managed to completely floor Genos. Every time. "I got it fixed up while you were being repaired!" he explained with a smile. "The last monster kinda did a number on you…and when I found you after I kicked its ass, you…barely had a hand left." The smile wavered, just slightly, but after years of observation and _knowing_ his teacher like no other, the slightest gesture resonated volumes to Genos. "And…it was covering where the ring was. Protecting it."

" _Saitama_ …" he breathed, painfully, reverently.

He gave a soundless chuckle, scratching the back of his head with a sheepish grin. "I know…this ring means a lot to you. But I was just glad that…" there was an unspoken _You're okay_ there, only voiced by the broken way Saitama's voice tapered off. "A-anyways, you did a pretty good job taking care of it, considering. There were still a few bangs and scratches on it though, so I took it to the jewelers myself to get it fixed up for you."

It glistened, just as it had when Saitama first opened the old box and slipped it through his finger, muttering a breathlessly relived, _It fits_! nearly six months ago. And when his husband gingerly performed that exact task right then and there, breathing out a warm, _It still fits,_ Genos simply knew there wouldn't be anyone else for him but this _impossible, wonderful_ and _everything-at-once_ man before him.

What Genos didn't know was how they ended up in a crumpled heap on the floor. But that didn't matter to him as he clung to his husband, oil smudged all over his face and Saitama's shirt, breathlessly happy and so very much in love.

 _Every time._

Every moment they shared together would be like this.

 _Every day_.

This warmth, this bliss,

 _For the rest of their lives_.

"Yeah…" Saitama mumbled from beneath his husband's metal body, basking in the affection that had slowly become part of their daily routine. Still, as much as he loved him and as much as he cherished these moments, Saitama could only take so much. Especially when a pair of lips started mouthing the skin of his neck, getting a bit too eager and prompting a snicker from him. He patted the blond head once before drawling out a matter-of-fact, "You know you're still not gettin' any, right?"

Genos made an embarrassingly bewildered (and alarmed) noise at that.

Saitama scoffed. "You heard me." He sat up and stood, slipping out from under Genos, out of the romantic atmosphere, and back into their (relative) normalcy. He raised a brow at the disbelieving look Genos was giving him from the ground. "That was the deal we made on our wedding night, remember?"

No, Genos, for the life of him, couldn't remember that at all.

He had been preoccupied with more…pressing matters that night. Like his Beloved in a sinfully short wedding dress, thigh-high stockings and garters disappearing beneath a coy curtain of lace that, upon sight, had Genos momentarily short-circuiting. Or the small hitches in breath his husband made as he hiked up the dress while teasing his dripping cock out of the matching white-laced underwear. Or the sensation of utter ecstasy as he drove deeper into the searing heat of his lover's walls, stocking-clad legs hooked over his shoulders and nylon rubbing against his cheeks has he drew fervid moans from that sweet, sweet mouth he couldn't get enough of.

There might've been _some_ talking involved, between the cries of _more, faster, harder,_ and _deeper_ ; maybe the conversation took place sometime between his darling's snarls of _I fucking married a goddamn pervert, didn't I?_ when Genos was between his legs, insisting that he leave the dress on, and the breathy string of _Haahn…Should I—ah!—kill King, or—oh, God!— t-thank him_? when Genos flipped them over to watch with not-so-silent reverence as his husband rode him unabashedly, bridal veil spilling over defined shoulders and shimmering under the moonlight. He wasn't sure. He'd have to revisit the footage he (secretly) recorded again to be certain.

For that moment though, no Genos did not remember. He shook his head.

"Get wrecked and it'll be just you and your hand for a week," Saitama helpfully elaborated.

Genos _definitely_ didn't remember saying 'yes' to this. "W-wait…" he started weakly. "Darling, y-you can't be…"

"Or…for however long _I_ can hold out." Saitama shrugged as he left Genos with figuring which were the lesser of the two evils he was dealt with.

 _Damn_. A week it was.

"Can we still cuddle?" Genos asked miserably from the floor.

Saitama snorted. "What kind of question is that? Of course!" He held back a chuckle as Genos immediately perked up. "C'mon, you still haven't eaten dinner. What did you do all day, anyways? And what's with the crying—I don't need to bust someone's head open, do I?"

Genos shook his head, knowing full well his word would spare thousands of dollars' worth of property damage. "No, everything's perfect." And of course, Saitama, His Heart, just gave him strange look before shrugging, none the wiser.

Of the terrible trials and tribulations he had just put Genos through and the unfathomable joy he gave him for his troubles. It was kind of pathetic, really. Still…

Genos looked to his own finger and felt something fall into place; not a glittering piece of metal, but something he had thought was lost forever in a sea of fire and hatred; something healed, nurtured, given, and returned. It was reflected here, catching light and echoing its partner's brilliant glow.

Yes, there really wouldn't be anyone else, Genos reaffirmed as he trailed after his husband, the twinkling of a band of gold under the kitchen lights and the sight of the grin of his husband's lips making him fall even harder.

They were inevitable, after all.

* * *

Eventually, yes. Saitama wheedled the reason out of Genos as to why he crying that night. He felt awful and Genos felt stupid. That, too, is inevitability.

* * *

 **Notes** :

*= Shout out to _How to Train Your Dragon_ fans out there ; w ; I still love the series~

I bring you schmoop for my first fic this year. And don't ask about the ending part either because I don't know. All I know is that the kinkshaming from Saitama will never stop. Also cyborg crybabies because I'm sorry. Also sorry this is OOC of them but their being so happily and stupidly in love with each other is my kryptonite.

Speaking of krypton(ite)…

This story idea actually came from my chemistry teacher's experience that he shared with me back when I was in high school. He was working at a lab before he become a teacher and always took off his wedding ring for safekeeping. One day he just couldn't find it. He told his wife (he was terrified, I imagine) and she just looked at him and said, "Well, I'm not buying you another one!"

He ended the story with a sweet, "So that's how I ended up happily married for over forty years— _without_ a ring."

((It's so sweet, they work in the same school and back when I was a student there, I would see them after class walking down the hallways together, always holding hands. UUuuughhhhh…relationship goals))

Genos keeps his wedding ring in a compartment on the suprasternal notch (the dip between the clavicles and neck); kind of necessary when Genos is used to having limbs torn off—and not to mention that he uses his hands to incinerate things (among various other types of attacks). He likes to take it out and wear it when he's at home, however.

Saitama (because his specialty is punching) keeps it in a short chain around his neck, tucked into his suit when he's in his hero costume (because Genos wanted to match), but when he's home or while he's casually out, wears it normally on his marriage hand's ring finger. He mostly punches with his right hand anyways.

Notes on wedding rings:

Typically, the couple shops for the wedding bands together, but some choose to pay for their partner's. With Saitama and Genos, I'm guessing Saitama thought that hey, Genos paid for Saitama's engagement ring so he should take care of getting Genos's wedding ring, right?

Also, it's suggested that you buy the wedding bands at least two months before the wedding day. And of course, Saitama put it off (poor bby was probably nervous and indecisive).

P.S. A large chunk of Saitama's savings went into that ring, if not most of it. (Including the money Genos gave him for rent.) Genos knew this and considering how much of a—ah… _thrifty_ shopper Saitama is, it meant a whole lot to Genos.


	8. Index and Previews: Vol 2

**Index: Volume 2**

* * *

 **7 Punch** : _Delta_ (or a slow burn followed by a slow dance; continuation of _Omega_ and _Alpha_ )

 _Something shifted— something that was once certain, etched upon the black and white of what had been written between them. It quaked beneath the earth, crumbling and cresting the foundations under their feet as the tempo hastened like a heartbeat upon an incredible and cataclysmic revelation. Something had_ changed _. But that wasn't surprising. What was surprising to Saitama was that it wasn't so bad._

 **8 Punch** : _Trial and Error_ (or four times Genos gets cockblocked and the one time he finally has his Sensei where he wants him) **NSFW**

 _Why was it that when Genos had silently suffered with his previously-thought unrequited feelings, he was made to endure the double-edged sword of endless hours alone with his Sensei, but now that he and his Beloved were finally dating, they couldn't have one_ (intimate) _moment without something popping up and making Genos want to scream? And unfortunately, not in the fun way._

 **9 Punch** : _A Walk in the Park_ (or while a psychopath is on the loose, Genos takes a stroll down memory lane. _Saitama's_ memory lane)

 _He was prepared to do anything in the name of his Sensei and in the name of justice. That included chasing down the villain that swore revenge against his teacher, jumping after him through a tear in time itself, finding himself thrown roughly 13 years in the past, and yes— even vigilantly protecting the twelve-year-old that would become the strongest hero. It was just a bit...unfortunate he couldn't obser— ah,_ guard _him a bit closer. Lest he create an alternate universe. And Sensei would definitely be disappointed in him if he allowed that to happen._

 **10 Punch** : _Delirium_ (or Saitama's hot and says things that makes Genos blush) **NSFW** -ish

 _This was punishment. Borderline torture. For what? If Genos were a betting man, he'd put this month's rent money on calling Saitama "Sensei" when they were intimate, deliberately against his flustered lover's wishes._

 **11 Punch** : _180_ (or Saitama doesn't know how to deal with his self-proclaimed Sensei who nearly gets himself killed on a weekly basis; continuation of _Reversal_ )

 _It wasn't like Saitama minded. It was kind of nice having someone around all the time. Even if he did want Saitama to call him 'Sensei'— and like_ hell _that was happening. Plus, he was nice to him, they mostly split the chores (Genos seemed to have been equipped with all sorts of gadgets for housework), and he actually did teach him some things that might've taken Saitama much longer than he'd like to admit to figure out. He just wished the guy would let him help every once in a while. And for him to quit nagging him to calling him 'Sensei.' The last part especially, since Genos does it in his sleep._

 **12 Punch** : _Pensieves and Pen Pals_ (or Genos writes to his soon-to-be-teacher and reminisces of his triumphs in the Triwizard Tournament, and more importantly, how he attained his real prize: Mister Saitama; continuation of _Flick of the Wrist_ )

"Ah, yeah...can someone please hurry? My hands are tied up and my nose itches." _Two pairs of eyes widened, unbeknownst to one another. Well, that was up until they both gave a yell of_ "Saitama?!" _At that, they locked eyes, glaring hard. What followed was what spectators could only describe as a squabble over the grumbling voice coming from the sarcophagus. Headmaster ONE could only shake his head, muttering something that sounded an awful lot like "I saw this coming. Why didn't I stop it?" Headmaster Murata beside him shrugged._

* * *

Notes:

It may take me a while, but if you have an idea you'd like to share with me, I'm all for it~


	9. 7 Punch: Delta

**7** **Punch** : _Delta_ (or a slow burn followed by a slow dance; continuation of _Omega_ and _Alpha_ )

* * *

Genos's homecoming wouldn't be met with much fanfare.

He would arrived Sunday afternoon, a week since their last conversation with a door and unspoken words standing between them. A week since he first saw his Sensei in the throes of passion and desperation. A week since Saitama lost himself in a torrent of primal desires and prejudiced physiology. A week since he sent Genos running out the door while he had a hole in the floor to fix and, strangely, a knob on the door to replace. A week since that first crack formed in the foundation built where each of them stood.

It would just be any other day.

After all, Saitama supposed it would happen sooner or later—that someone would discover his nature. It was all about timing—and that was something Saitama was awful at and figured it was something that was disinclined to change anytime soon. But just as well, he supposed he simply wouldn't care of it.

Or so, he tried to tell himself.

Because this was different. This was _different_ in ways Saitama couldn't voice and in ways he wouldn't dare dwell on. Because something— _something_ in him just knew that Genos was a goddamn _fucking_ _ **Alpha**_ and the fact he caught Saitama in the midst of his heat, panting and moaning like a bitch, trembling and _desperate_ for a cock to fill him—

A wave of nausea hit him hard. He never cared for anyone knowing about his nature. That never mattered to him. If they treated him differently, derided him for his unnatural plainness, his unappealing characteristics to Alphas, that was fine too (but mention one word about his baldness, however— _that_ was another thing entirely). It never mattered to him and his strength made sure that none of that would _ever_ matter to him. He was an Omega. It's who he was and something he can't change. Even if he were given the choice, he _wouldn't_.

So then why did it feel like he had just disappointed his self-proclaimed disciple?

Felt like he had outright lied to him, felt like he did something _wrong_. Was it because he was stronger than him? Was it because Genos had forced the title of _Sensei_ upon him without knowing millennia of hierarchy and heritage would have Saitama bowing at Genos's feet?

 _No_ , it wasn't that either.

It was because, now, Genos should realize that Saitama isn't what he expected at all.

From his training regimen, to his inability to ever get anywhere on time, to his ignorance of the Hero Association, to his hero ranking, to his biological nature. They all made up Saitama too. And how many more times would it be before 'surprising' and 'unconventional' rotted to 'disgraceful' and 'disappointment'?

It was a strange sensation, like gyres beneath ocean waves, a maelstrom beneath the depths. Of emotions he hadn't expected to feel in a long time as he had been swept beneath the tides of apathy. He knew their names, scented and tasted them in the air of years long gone. Anxiety, apprehension, worry, guilt…

But not shame. _Never_ shame.

 _((Guilt is what you feel when you have done something wrong. Shame is when you_ _ **were**_ _what was wrong.))_

There was simply no room for it.

So the evidence had been hidden away, packed into an unassuming box, swept into the farthest reaches of the closet, and veiled with the clutter of lazy housework accumulating after a week as Saitama, still in his pajamas, peered up from his manga at the other's approach upon the turning of a doorknob and the heavy footsteps that echoed like a heartbeat in his ears.

* * *

His homecoming wasn't met with much fanfare.

The _"Welcome back"_ Genos was greeted with at the door ushered in a strange and soothing sensation of familiarity and normalcy, calming storms and taming tides. Genos felt like he could almost sink into its embrace and claim those haunting memories of sweat-slicked skin and hungry moans as mere dreams, lovelorn and lonely as he continued to long for what couldn't be.

 _((But that would be taking the easy way out.))_

Because unbeknownst to Saitama and as terrifying as it was, Genos knew he loved the man too much to simply allow things to _be_ between them.

So he stepped into the room, one foot after the other, unsure of which direction to go and uncaring of it as long as it took him _forward_.

 _"_ _Thank you, Sensei."_

* * *

It had been two weeks since Genos returned and things were… _"Tense"_ might have been the word but then again, it might've also been the understatement of the year. It might've been the deafening silence they engaged in or the curt conversations that filled the spaces in-between.

Or it might've been the eyes he felt staring far too often and far too intently at him.

The sensation came so frequently that the shivers ceased and paranoia shifted to annoyance. He could trace the trail those black and gold eyes left as though they seared the skin beneath his clothes. It grew vexing, a niggling thought that refused to sink below the mundane tasks he performed and gratingly situated itself in the forefront of his mind.

Everywhere they went, he could feel those scanners roam across the planes of his back, focus on the most subtle of movements he made, aimed on him after every bored sigh or disgruntled mumble. A strange intensity glowing behind them dulled and dimmed to a bland stare whenever Saitama made a move to catch him in the act. Genos never looked away, his silence almost daring him to question it. It unnerved him, dangerously so, and was stifling in their close living quarters.

It was especially intense when Saitama chose to forego a shirt. Risky territory, in retrospect, after the incident three weeks ago. But it wasn't as though that was Genos would complain about since Saitama had always done that…and even if he did, why should Saitama care? It was _his_ apartment after all.

 _((His territory, his home_ , _he would_ _ **not**_ _be made the outsider here—))_

He felt the skin of his neck prickle from the other's gaze before Saitama finally gave a sigh. "Okay, I've had about enough." He turned, unsurprised by the quiet gaze he was met with, a wordless demand or a silent challenge. Saitama felt a vein tick against his forehead. "You have _got_ to stop that."

"Stop what, Sensei?" Genos asked, tone placid.

And the staring resumed. _"That!"_ Trudging over and plopping down across from him on the table, Saitama glared at the other expectantly. "You're always staring at me. What gives?" He knew what he was doing; Saitama was sure of it. There was no way a person could just _happen_ to stare at someone several times throughout the day for uncomfortable durations of time without noticing. They'd have to be completely insane first.

Genos blinked, a slow look of realization coming to him. "I apologize for making you feel…uncomfortable." Did…did Genos really think Saitama wouldn't notice? _Right_. Completely insane…but Genos wasn't; Saitama only seldom questioned the other's mental state. He was still right, however; Genos _was_ doing it on purpose. "That was not my intention."

Saitama frowned, giving the other a hard look. Dare he ask…? "So what _was_ your intention?"

The question, at the very least, seemed to throw Genos off. "I…" Saitama expected more but as he waited, nothing followed (saved for a bizarre humming noise that sounded like an overheating laptop). He raised a brow and frowned when all Genos did was shift his gaze to the wall. Well…this was new. For once, Genos might have nothing to say.

 _((Might have nothing Saitama desired to hear.))_

Too bad Saitama wasn't buying it. " _Genos_." The other stiffened immediately, a reflex borne of absolute obedience and dogged fidelity. Saitama sighed; it was also the last thing he wanted right now. He needed the _truth_ —and not just what Genos believed Saitama wanted out of him. "Is it because of what…you walked in to a few weeks ago?" _Especially_ if he thought that was what Saitama wanted out of him.

Genos almost seemed to flinch and the hesitation was enough as something crumbled and crashed all at once, the tiniest shudder from the other sending a wave of ugly panic coiling in Saitama's gut and all too easily twisting to defensiveness.

"Look, I _swear_ Genos—"

 _((No, this has nothing to do with me—))_

"If you have a problem with me being an Omega, just up and say it."

 _((_ _ **I did nothing wrong**_ _—))_

"If you have a problem living with me, trying to learning from me, or just being around me—"

 _((So don't you_ _ **dare**_ _make me feel like this is_ _ **my**_ _fault—))_

"Then you know, you have every right to—"

 _"_ _ **NO**_ _!"_

And all at once, those thoughts, poisonous and self-justifying, dissipated at the outburst, the opposition and objection resonating clearly while the softer overtones of sheer desperation and terror in the other's voice resounded in Saitama's ears.

"Please, don't—I'm sorry, Sensei, please I didn't mean to—It was not my—that was not what I—" Catching himself, Genos fell silent. Something like ' _twenty words'_ formed by his lips and Saitama could only sit frozen as the gravity of the situation sunk in when Genos spoke again. " _Please_ …don't make me go."

Oh.

 _Oh_.

Oh, he fucked up.

Glad he always kept tissues nearby, Saitama pulled a few sheets out of the box on the table and knelt down beside Genos. He gingerly lifted the other's head, somewhat glad the other at least didn't recoil at his touch, before groaning. "Ah…stop…you're making a mess." He was rather unsurprised to find that once again, he had inexplicably driven his disciple to tears.

Also unsurprisingly, that did little to alleviate the problem. The little streamlets of oil only flowed thicker, much to his annoyance. Saitama sighed, blotting away the streaks; after the first time, he learned that wiping them only left unsightly smudges that did little to help the situation at all. He couldn't very well help Genos calm down if he was resisting the urge to give an inappropriate laugh.

And as Genos patiently allowed himself to wallow a little as his Sensei did this, Saitama guessed that _this_ might calm him down, however: "I'm not…I'm not telling you to leave. I'm not kicking you out—don't worry about that, all right? Whether you choose to stay or not is entirely up to you." And when Genos met his eyes, looking slightly less miserable and dumbfounded with so much gratefulness, Saitama had to swallow down the bile rising up his throat from the knowledge that _he really fucked up_. "You've been acting weird, all right! It's not exactly my fault for thinking it's because of…what you saw," he (attempted) to rationalize.

In retrospect, it really _was_ sound conclusion. He truly thought he had up and traumatized Genos for life back there. And, after all, why else would Genos stare at him so intently? And right after coming back from Saitama's decreed week-long exile? Why would he gaze so long at him after witnessing his _Sensei_ in such a vulnerable and vulgar position? The first and obvious deduction drawn from the events was simply that.

 _((The second deduction wasn't worth considering at all.))_

The answer came in this simple: "You were avoiding me."

Saitama blinked. "What?"

"Since I came back," Genos replied, hands clenched atop his lap and jaw tight. "You've hardly looked at me. Or spoken to me. I thought…I thought I did something wrong…"

"Oh," Saitama breathed. "Damn." Okay…so this _was_ his fault. Partly, anyways.

"Did I?" Genos quietly implored and if Saitama thought he couldn't feel worse about this, he was very, _very_ wrong.

In truth, this entire situation was just _plain_ wrong. Wrong in so many ways that Saitama didn't even know where to start. From this Sensei-disciple arrangement down to the codons within the double-stranded helix that dictated so much of their lives without either of their consent. But one thing was certain, however. "No. I didn't mean to…" So what if Saitama was an Omega? And Genos was an Alpha? That never— _never_ mattered to him. None of this stuff did. "Sorry," he finished simply. On _his_ end, there was nothing to worry about.

Genos shook his head. "You shouldn't be the one apologizing—"

"I damn well _should_ be," he scoffed.

No, the problem was never what _nature_ had gone and written itself out on someone's fate, if even such a fickle thing ever existed. No, what mattered was how they handled the hand they were dealt with. Nevertheless, there were some things that needed to be clear with them; some things that neither fortune nor inheritance had a hold on:

"But you haven't been exactly…" _Honest_ was the word Saitama wanted to say. Was Genos being honest with him? He sure as hell didn't sound like it three weeks ago. And no matter what Genos said after Saitama opened his mouth, he needed to hear it. "I'm an Omega. Does that bother you?" Both of them did. Even if Saitama was going to regret hearing it, just as he was sure he was going to regret saying this: "You can go over twenty words if you have to."

Genos wasted no time, answer immediate: "Sensei is the strongest man I've ever met. The most amazing and among the kindest as well. If it had not been for you, I would have surely met my mortal fate. Had it not been for your direction, I would still have been a merciless being, delivering a cold and callous sense of justice without my humanity and your wisdom to guide my actions." And when Saitama thought he couldn't feel more uncomfortable, he was proven wrong once more. "Sensei, I should have told you this sooner, but your being an Omega is simply one tiny facet that makes up who you are as an entirety. And it is you, all of you, that I choose to follow."

Saitama opened his mouth but was instantly cut off as Genos started again, sparking a strange mix of irritation and gratitude.

"Do not think your nature changes any of that—that your nature makes you appear weaker or stranger to me." His words echoed that of a certain conversation held by an entryway, wood and metal and a thousand things that didn't exist between them keeping their sincerity from Saitama's ears. But now—now, it was just them, an empty room where the words would reverberate against thin walls and the pale lights overhead would only serve to brighten the fire in Genos's eyes. "You are—you're my _Sensei_." And never before had Saitama felt the sheer weight of those words. "I will always value, respect…and cherish you."

And he had heard this all before. It was nothing new. This was among the strings of praises and tirades of adulations in his name. Yet…it was different—somehow.

Maybe because there wasn't a door between them this time. Maybe it was because he could see Genos's eyes and his oil-stained face. Or maybe because this was the first time Saitama had been truly— _scared_ – to lose something between them.

Nevertheless, "That…" he breathed, allowing the words to settle and the storming thoughts to quiet, "That doesn't answer my question."

Because _yes_ —as much as he _pained_ to admit it—this was unchartered territory, he was pretty lost, and he was positive what he was feeling now was _fear_. He had never wanted this; he was fine with being alone; he was fine with being a hero for a hobby; and fine with an empty apartment to come home to every day. He'd lived long enough without anything tying him down or anything tethering itself to his side to know he didn't need it. But _god_ help him _—wanting_ _it_ was something he had apparently, inadvertently, and irreversibly gone and learned himself. And what he learned to live with and what he learned to want to remain—he didn't want any of that tarnished and tainted just because of something that had fucked up in their evolutionary line.

And _this was so wrong_. But it wasn't anything that could be helped.

Especially not when Genos gave him a weary smile, taking a tissue and (unintentionally) smearing streaks of oil all over his face. "I thought you were going to point out that my response didn't require exceeding my word limit."

And perhaps for the first time, his disciple defied him as Genos said nothing more.

But maybe, in a way, he did answer. Either by his refusal, his avoidance in a straight answer to his question. Or maybe, it was in the way Saitama had phrased his question—another, smaller message beneath the audible words, a niggling voice at the back of his mind, tormenting thorned embraces squeezing something in his chest so tight it might just pop:

 _How do you feel about me as an Omega?_

"That too," Saitama replied as he took the last of the tissues and attempted to fix what now looked like cheap mascara smeared across Genos's eyes. "Ah…we should go out for groceries soon."

But he would let it drop—for now. Because right now, he supposed he didn't need to hear those words. Didn't— _ever_ have to hear those words. Because they didn't matter. And because right now, all he needed to know was that he was still _Sensei_ in Genos's eyes…that Genos wanted to stay.

That would have to be enough. "There's a sale on vegetables this Friday, Sensei," Genos supplied helpfully with a tiny smile.

"Really? Great! We can pick up more tissues while we're there."

It was absolved, a vacant victory with honeyed words over forming wounds, a bandage over something breaking.

* * *

Sometimes Saitama had to commend the creativity these monsters had; most of the time however, he just wondered how on earth their themes managed to create such absurd creatures.

A disco ball monster, in this case, that rampaged through a middle school, the moon hung high in the empty sky that night providing ample borrowed light for the creature to decimate the surrounding area with its fiery beams. It declared itself as _A Fever You Can't Sweat Out_ as it ravaged the district and caused a number of school children, parents, and staff members to flee.

What it had against school gyms, Saitama had no idea but he really wasn't all that keen in finding out. One punch ended it (as they all did…) before the thing up and shattered to a thousand shards falling lifelessly to the night air in a flurry of glitter (like the death of the 80s).

"Sensei!" Genos called out, leaping over the remains of a wall.

He glanced over and hummed in acknowledgment.

Saitama was careful to avoid the fragments littering the floor and the flames licking the fringes of the ruined building—yet another mess that had to be addressed to the hardworking construction companies that dedicated their days to rebuilding the concrete jungles before another disaster threatened to topple it down. It had been years since he became a hero—he had defeated so many creatures and villains that he lost count of them all. Nevertheless, new ones took their place and crime and chaos was at a constant high.

"Well…looks like no one was hurt, at least…" Saitama murmured. "But why were there a bunch of students hanging around here at night?"

Genos picked up a banner, fallen to the floor with in a pitiful heap. "This might have something to do with it…"

"Oh," Saitama replied simply, giving a once-over at the crumpled and torn words, an artistic symbol of two people entangled in an embrace. "Never really got what big deal about these the couples dances or why they put them in cultural festivals."

"I heard it was adopted from a foreign custom decades ago. It appears they're making a comeback—or rather, attempting to, to ensure that the changing times wouldn't forego traditional mindsets." Genos explained, allowing the paper to flutter to the ground. "Its designed purpose is to prepare younger students for the intricacies of courtship."

Saitama scratched his head as he stepped over to the younger. "Ah? How so?"

Genos fell a step behind his teacher as they started towards home. "Dances were seen as a show of intimacy and, for the dominant partner, an opportunity to display their skills in leading and coordination while with the submissive partner could demonstrate their willingness to follow their mate and entice them as well."

"Really?" Saitama blinked. "That _is_ pretty intricate. I really doubt these kids get all that from dancing though."

"No…I don't think so either." Genos agreed. After a beat, he added. "For them, it's simply a time to enjoy being with one another."

Saitama let those words linger for a while. He knew the other didn't necessarily care for recreation—after their time at the summer festival, he had hoped the guy would at least livened up a bit, but other than expressing gratitude for their time together, Genos didn't appear to have any inclinations for periods of relaxation and enjoyment. At least, he didn't voice them out loud. Saitama frowned. The guy was only nineteen after all and had been a hero since he was fifteen.

But as Genos stood there, among the wreckage and decimation, a thought struck Saitama rather suddenly: _Did Genos get to experience these sorts of things?_

Surely, he had been forced to mature at a young age due to the tragedies that molded his life, but that didn't mean that Genos abandoned his memories of happier times, casted them aside as he devoted his life to his seemingly sole purpose. A burden he shouldered willfully in solitude.

In a way, Saitama was glad that the couples dance petered out if what Genos informed him was truly the intent behind it. Too many kids were forced to grow up too quickly, allowing ancient voices to dictate a time that should remain joyful and innocent, far away from the critical eyes of those around them. Those precious years should belong to them and them alone.

He sighed. _"_ Things would be simpler that way, wouldn't they?"

Genos paused mid-step. "Sensei?"

"I said, 'what the hell are you anyways?'" It _really_ was a good thing he could come up with things to say on the fly. Plus, it came in handy with confirming his suspicions.

"I—am an Alpha, Sensei," Genos replied, wavering ever-so-lightly.

Saitama shrugged unsurprised. "Heh. Figures." He totally called it.

"Although, when I was fully human, no one believed it."

 _That_ was a bit unexpected, however. "Eh?"

"I was rather small, especially for an Alpha," he started. "Studious too. I hadn't had interest in much else other than working hard for my family."

"I guess in that…not much has changed," Saitama remarked, scratching his head. A puny Genos, however…he certainly can't picture it very well.

"And…yourself, Sensei?" Genos tentatively asked. "How were you back then?"

Saitama froze. "Ah?" And when he looked back to the other, he found him staring back, awaiting a response.

Damn. Well, he supposed it was his fault for bringing it up.

"I was actually pretty clueless." He cued Genos's wide-eyed gasp perfectly; Saitama shook his head. "Funny thing: I found out about being an Omega when I went into my first heat. I mistook it for dying, actually." He frowned, the hazy memories starting to form silhouettes and echoes. "Yeah, it hit me after school, but luckily the infirmary was still open. I guess my timing isn't so awful in that case. I mean, the school nurse chewed me out for not paying enough attention to my Biology class but she let me off because I knew my Health pretty well." He could almost see the plain white uniform, brown bobbed hair and warm eyes. But he had forgotten her name. Saitama shrugged. "She taught me about the basic stuff—suppressants, tracking my cycles, how to take care of myself during heats, safe sex—all that." He hummed as some more of her voice lilted in and out of his conscious. "She said I was big for an Omega in my age group. I guess that made it easier for me to blend in back then."

As per usual, Genos absorbed the information readily. "Were there others who knew of your nature?"

Saitama shook his head. "Nah. Got mistaken for a Beta nearly all my life except by doctors and nurses. I didn't bother correcting the rest of 'em." Alpha, Beta, Omega…what was the point in all that? "I mean, does it matter?"

"Sensei…" Saitama didn't know what to make of the breathy way Genos spoke his imposed title. All he was glad for was that he at least didn't have to face him as a wave of uneasiness hit him, as it always did, when Genos got a bit too reverent. "You're right. It doesn't matter."

"Heh. What a weird pair we make." It wasn't a bad feeling overall. It was just…something Saitama wasn't used to (and honestly, it wasn't something that he _wanted_ to be used to).

Genos was supposed to be his subordinate, but from the very start—it didn't feel right at all. Something that easily separated them by a simple name, an ordered structure that Saitama himself never asked for. But Genos…needed it. Wanted it. Whatever it was between them, as unconventional and inimitable as it was.

It wasn't a hierarchy—no, nothing like the role blood and tradition had tried to force. It was a bond, a very _human_ connection, entangling and carving a name for itself within the days spent by each other's side and the hollow blazes of battle. And with that, nothing else mattered; not genetics and not cybernetic limbs. "By the way, you _are_ human," Saitama remarked as Genos's previous statement recurred to him. "Don't think you're any more or less just because you have _way_ more iron in your system than the rest of us."

His footsteps halted. "S- _sensei_ …"

Saitama gave a wry grin to himself, back towards his self-proclaimed disciple as he headed for home once more.

Wait, was that…was that a fan going off (loudly) somewhere?

* * *

Unbeknownst to him (well, not really; Saitama had a feeling) Genos smiled, wonderstruck and overcome at his Sensei's breathtaking words.

And unbeknownst to Saitama (this time for sure), several scenarios passed through Genos's mind at lightning-fast flashes—the vast majority of them causing his cooling systems to work in overdrive. Three small words threatened to slip past his lips, unknowing and uncaring if they were to reach his Sensei's heart or to crash miserably to the unforgiving earth below.

But _timing_ was a key thing, he had learned. Whether in the soft trickle of suns and moons passing in the sky or the terrifying torrents of triple-time tempos in battle, and perhaps in the most intricate and convoluted thing he was ever going to attempt. And now…beneath the moonlight on an abandoned street, the night air whispering sweet romances as a breeze wafted by, and the intimacy of seclusion, them alone, a silent space that only needed Genos's response to fill it with new beginnings, possibilities and promises born from the supernovas in the tiny universe they shared—

—Genos sighed, knowing very well what to say: "They're actually titanium alloy but—"

" _Ack_ —whatever!"

Genos held back a hopeless laugh.

He would make the next one count.

* * *

"I've never experienced those dances."

"Eh?" Saitama paused, chip midway between the bag and his mouth. "We're still on about that?"

"Just…making conversation," Genos replied. "That, and the movie we're watching—"

"Oh, right," he nodded.

It was only a small scene. A gala of some sort, where the main target lost its pursuers in a sea of couples waltzing on the floor. To blend in without causing a riot, the main characters joined the festivity—with the protagonist unknowingly dancing with his stalker.

Saitama rolled over on his back, watching the lights flicker on the ceiling. "Yeah, I never actually went to one either." How this series managed to produce another sequel was a mystery to Saitama. Just like how he managed to escape ninth grade with both his legs intact. "Never forgot those damn classes they made us attend though. _Man_ those three-beat counts still haunt me."

Genos turned to face him, face alight with that unnerving intensity. "You learned how to dance?"

"All of us did." Saitama sat up, arching a brow. "You didn't?"

"No…" He hummed in thought. "I suppose my former school district removed it from the curriculum after more progressive views took hold and the older generation's viewpoints—"

"Okay, one: you're not _that_ much younger than me," the elder drawled. "Two: count yourself lucky. I never got anything out of learning how to waltz."

Other than bruises on his legs as his clumsy partner, a kid with thick-framed round glasses who nervously floundered around the whole period as he attempted to construct his own lopsided rhythm, much to the dismay of Saitama's aching feet after around the fourth time they fell over.

When he was brought back to the present, however, Saitama barely made out some quiet mutterings about _timing_ when Genos's eyes met his—and immediately darted away.

Oh.

 _That_ was interesting.

"What was that?" Saitama asked, shooting the other an expectant look.

Saitama's eyes must've been playing tricks on him, as confirmed by the instant and unabashed answer (and question) of, "Will you teach me?" Unsurprising and rightly so since _"forthright"_ and _"blunt"_ was more of Genos's style (the former after one short lesson) with a dash of _"silent ferocity"_ when he really wanted something.

Still though. "Were you…were you listening at all?"

"If it's something Sensei learned then it is something I want to learn as well," Genos adamantly declared.

"Then go sign up for classes," he replied flatly. Saitama was sure he saw Genos deflate. No tricks of the light there. "I'm sure there's something like that at the rec center—"

"But they're not you," he implored. "Please? I want to learn. From you."

Saitama felt his left eye twitch. "You're a brat. You know that, right?"

It was infuriating how happy he looked, knowing he won.

* * *

 _Timing is everything._

* * *

"All right…closed position." A metal hand was nearly crushing his hip but at this point, this was least of his worries. It's not like that or any clumsy footwork from Genos would leave bruises anyways. "Okay so if I remember this right—and mind you, I probably don't—first, you gotta keep that one-two-three beat in your head. On the first beat, you step forward with your left foot and I step back with my right and—"

"Will you lead?" _Damn_ this guy. And while Saitama was sure he didn't voice that out loud, the face he was making should have relayed the message just fine to Genos. "My apologies, Sensei…but it may be easier for us if…" And _damnit all._ "If you take the lead. I'll follow." Saitama can't tell him 'no.'

He blustered out a heavy sigh. "Fine. We'll go slow."

It won't be hard. Just mirror what he had been taught. Do the direct opposite of what had been drilled in his head. Just as he had his whole life.

And so, they danced.

"One-two-three, one-two-three," Saitama counted, more for himself than Genos, as the metronomic beats filled the room alongside the soft shuffle of feet.

There wasn't any music. The movie had been paused, splotches of color painting the floors. Not even the stars found their way to the cramped apartment's open balcony door. The silent serenade of the moon didn't care to attend either, its pallid glow darting behind a curtain of clouds as though too mortified or too uninterested to watch this debacle and instead scattered its beams away.

And that was fine.

No one needed to see this: Saitama—an Omega—leading Genos—an Alpha—in a crooked waltz without a direction between either of them and nothing more than a clumsy cadence to keep them together. Metal and bone occasionally knocked together unpleasantly, a fumbling apology following another stumble as stiff limbs from failing memory and frustrated tension clashed and dissonance assisted in the deepening the distance. It was every bit as awkward as Saitama had predicted and every ounce as nerveracking as Genos had dreaded.

At first, anyways.

Because _timing_ was a key thing—whether keeping count in grumbles and grunts over missteps and mistakes or in measuring its tempo in trials and tribulations, resonating in rhythm as something like fate or fluke delivered that _one_ golden moment.

The very one that orchestrated the stiffness to melt away to fluid movements, moonlight bathing the quiet district in its ethereal radiance; mechanical counting smoothing to an intuitive pace, the tiniest glimmers of galaxies in other skies flickering overhead unbeknownst to them both; Saitama, listening to the melodic whirr of something singing within his partner, the melody filling the silent space that they had both reached across.

The very one that upon the final beat, hands clasped together, a breath apart in closed position, something fell in place between them: simple and natural, unquestioning and uncontrolled, but more than that—

Something _shifted_ — something that was once certain, etched upon the black and white of what had been written between them. It quaked beneath the earth, crumbling and cresting the foundations under their feet as the tempo hastened like a heartbeat upon an incredible and cataclysmic revelation.

Something had _changed_.

But that wasn't surprising.

What was surprising to Saitama was that it wasn't so bad.

That was, until he met Genos's eyes, caught in those very same quiet and intent stares; the ones that seared his skin and trailed shivers down his spine as a gaze of molten gold memorized every detail until it was branded to memory. The one that echoed a meaning that Saitama hadn't yet been able to decipher up until now as the hand in his trembled and a shuddering breath escaped his mouth.

Saitama swallowed, a dangerous mixture of betrayal and excitement igniting in his veins. "All that, about wanting to learn the waltz just because I had to…that was a load of bullshit, wasn't it," he rasped. It wasn't a question. Just like how maybe—just _maybe_ —that discarded second deduction didn't seem so far off anymore.

And he had his answer—perhaps to all his questions or to the only one that really mattered—as Genos gazed back at him, a burning look in his eyes of utter _want_ , mouth forming a scorching, " _Yes_."

"You fucking _brat_ ," Saitama growled as one of them—both of them—surged forward, lips crashing to a kiss.

* * *

Delta:

del·ta

/ˈdeltə/

noun:

Denotes: change

* * *

-shrugs- I have no idea.

Notes:

I use Δ a lot when note-taking as a short-hand for "change," (change in heat, change in volume, change in velocity, change in pressure, and so forth) so it sort of fits? Technically, however, delta represents change of any changeable quantity, in mathematics and the sciences.

That line about guilt is from _Complications: A Surgeon's Notes on an Imperfect Science_ by Atul Gawande. "This was not guilt: guilt is what you feel when you have done something wrong. What I felt was shame: I was what was wrong."

…Also yes, that was a Panic! at the Disco reference ( _A Fever You Can't Sweat Out_ was their debut studio album and also because the thing makes fire from shooting lasers from reflected light sources and yeah).

Note: Japan does not have dances like school proms, _but_ they do have festivals which includes different types of dancing (usually folk and group dances, if I'm not mistaken). I am pretty sure they normally don't have couples dances. I am tweaking it here because, yes, I wanted to use the waltz as a metaphor (and parallelism).


	10. 8 Punch: Trial and Error

**8 Punch** : _Trial and Error_ (or four times Genos gets cockblocked and the one time he finally has his Sensei where he wants him) **NSFW**

* * *

It was glaring obvious when Saitama and Genos started dating.

It wasn't them standing a bit too close to one another or the fact that the appearance of one meant a high possibility that the other wasn't too far off. Nor the evident way the stoic cyborg's demeanor shifted from the dark and serious countenance to one of reverence and adoration when Saitama did—well, anything. It wasn't the fact that Saitama felt more comfortable when Genos was around, was more outspoken when the other was by his side, nor the fact that they'd been living like a married couple for months in domestic bliss with a bit of crime-fighting on the side.

No, they'd pretty much been like that since King knew them.

Now, there was absolutely no way of even mistaking their behavior as anything but romantic.

Because _now_ , King rarely saw Saitama go anywhere without Genos's hand in his, fingers laced intimately together, or an arm snaked round the hero's waist, keeping him protectively close against a metal body that was positively (and audibly) whirring with happiness. _Now_ , Saitama's title of _Sensei_ had been extended to _My Beloved Sensei_ (and a myriad of others that never failed to make the man about as uncomfortable as he was happy for his friends). _Now,_ the quiet looks of admiration and affection and bouts of praise had blown to obvious kisses (whether a small peck on the cheek, forehead, and lips or the steamier variant better made for dramatic partings rather than Genos going to the store to buy more kombu stock) and open declarations of love, more often than not from the cyborg's end.

But _now_ , it was also seeing Saitama smile a lot more (and blush too—the shade of red his ears could turn was certainly interesting), seeing the way he openly accepted the affection (he only made Genos stop when every last inch of his face was completely flushed), and seeing his friend generally more… _lively._ The bored looks were still there, but they were few and far between compared to before. And there was a brightness in his eyes that King had only ever seen a handful of times before he and Genos appeared one morning, hand in hand like it was always meant to be that way.

They were obviously dating.

And obviously, Saitama was his friend and hero and even though King knew he was a coward, he would stand by him and do his part to keep him was precisely why he was here.

King sighed, face reddening at the…mortifyingly _obvious_ actions taking place behind that door. Nevertheless, he clutched his new game along with the last bits of his courage and prepared to knock. Or, rather he would have, had his cardiac condition decided its _Roaring Engine_ could do a better job.

 _"_ _What—what's that pounding—?"_

Scratch that. That was Saitama, voice breathless as the shuffling from within stopped and King decided that he needed to bolt immediately.

 _"_ _The pounding hasn't started yet, Master…"_

And that was Genos, practically purring as he just implied—King gulped. That's it. He can't do this. ' _Someone, anyone…'_

 _"_ _I told you not to call me that_ _ **—AND THAT'S NOT WHAT I MEANT—!**_ _"_

 _'_ _Kill me now,'_ King mentally pleaded as his body betrayed him and stayed rooted to the floor. _No_ , he had to do this.

 _"_ _Forgive me, my dearest. I didn't hear anything apart from your breathy sighs and wanton moans—"_

As he headed towards cardiac arrest, King idly wondered if anyone had ever died of second-hand embarrassment or if being the first would make for an interesting epitaph.

" _Do you hear_ _ **that**_ _?"_ Saitama asked flatly.

After one terrifying second, there was a loud (and horribly disappointed) sigh from Genos and King felt just the tiniest trickles of guilt drip down his gut.

" _Let me find your pants…"_

King supposed it was only polite to inform them that Saitama's pair were in the hallway some feet behind him.*

* * *

Genos was grateful for Saitama's friends.

He really was.

His Beloved deserved to have people in his life who appreciated him, who cared for him, recognized his good qualities and accepted the bad (Saitama had a few; Genos was in love, not blindly stupid), and most of all, he deserved having people around that made him happy. That was what Genos wanted for his Sensei and he vowed, far before he offered his heart and received his Beloved's in return, that he would do all he could to see that happiness come to fruition.

Genos was grateful for Saitama's friends.

He just sort of wished they didn't come, _unannounced,_ when he was between his Sensei's legs, hand pumping his cock and two of his fingers stretching the tight walls of his would-be-lover.

 _"_ _Would-be_ ," being the driving point of Genos's frustration.

But that was fine. So _what_ if he endured humiliation levels strong enough to probably kill a man (but not a man in love) as he asked Doctor Kuseno to implement the, ah…"necessary" equipment for intimacy? So _what_ if it had taken weeks of gently coaxing his flustered Sensei to finally let Genos undress him, revealing inch by inch the smooth planes of hardened muscle that left Genos's visuals nearly short-circuiting? So _what_ if it had taken a bit longer than that for his Sensei to feel comfortable with Genos touching and worshiping his body? So _what_ if he finally had his Sensei beneath him, blushing so sweetly, a litany of lovely moans escaping from his lovely pink-kissed mouth just like he'd always dreamed?

And so _what_ if things had been going so well up until the intrusion?

((A bit more time and his Sensei would have hopefully ignored the fierce fighting spirit King emitted…Maybe he needed to speed along the process of preparation…? To decrease the possibility of this rather… _unfortunate_ circumstance from occurring again.))

So **_what_** _?_

Because _apparently_ there was some merit to playing out some scenario of a nameless fictional character riding a dragon-god into space to fight a meteor alien after failing to send said meteor alien to another dimension.* Which was ridiculous. His Beloved wouldn't need the dragon-god; he had already defeated both a meteor _and_ an alien by himself just fine.

Saitama's attention shifted away from the screen as he sensed a disturbance behind him. He turned, frowning in concern at what he saw. "Genos, you okay? You kinda have a scary look on your face."

"Yes. Just fine, My Heart," he said, not entirely sure if the murder in his eyes vanished yet.

And just like always, Saitama shrugged and left Genos to his own devices. "If you say so." And just as always, he was blissfully unaware of the plans that began to storm in the cyborg's thoughts to ameliorate the situation.

Meanwhile, Genos _sort_ of had an idea to propose to the Doctor. Not only that, but it would also make the experience more organic for his Sensei. It would be a benefit for the both of them.

Now he just had to sacrifice a bit more of his dignity to make the call.

* * *

" _A-Ah!"_

Sensei was exquisite like this.

" _G-Genos…_ " Leg thrown over a metal shoulder, hands clutching the sheets beneath him so hard, the fibers were beginning to fray, and eyes hazy with the brilliant glow of utter want. "C'mon…don't just— _nng—!_ "

"Keep singing to me, Beloved…" Genos murmured as he trailed kisses and bites down a muscled thigh. "Let me hear that lovely voice when you beg." He reveled in the low moan that earned him; it seemed his Sensei had a bit of kink for sweet-talk though he'd probably deny it if Genos ever voiced his observations out loud.

That worked out well for both of them. Genos wanted to lather his Darling with words of adoration and it just so happened that sometimes he'd say something that either made Saitama go weak in the knees or had him panting against his mouth.

All good distractions from the uncomfortable feeling of having three fingers scissoring his ass.

Leg falling to hook around his hips, Genos let his hand idly map the roads of taut flesh around Saitama's waist. Mechanoreceptors hypersensitive to the feel of the quivering body below him traveled a bit farther before metal fingers gave a lazy stroke to the erect cock standing proudly against his Sensei's belly. The response was nothing short of an utter delight to witness, hearing his Darling keen and tremble as Genos pumped his hand over the shaft before thumbing the slit to smear the pearly drops over the engorged head. And his love, his _beautiful_ , _enticing_ Sensei gasped and arched to his touch, a sob escaping his mouth, tears beading at the corners of his eyes, and Genos swore a lovelier sight had never existed.

He shivered as the compartment between his legs opened, eyes never leaving the precious view of his Beloved Sensei laid out before him. He loved this man so _much_.

And he couldn't wait to ravage him.

On Saitama's end, the hero was pretty sure he'd never felt torture quite like this.

" _Please_ ," he whined, thrusting up to meet more friction from heated metal and jolting when his sudden movements brushed the fingers stretching him against his prostate. He was pretty sure his mind just blanked at that moment, caught between a moan and a curse while the burning gaze in those molten gold eyes above him intensified.

And it's _so_ _ **good**_ —the steam in the air, the heat on his skin, the electric sparks that ran through his body at every touch, Genos above him in semisweet-sadistic glee as he watched his _Sensei_ fall apart at his hands.

Something in his chest tightened when he felt the fingers leave his wanting body and Saitama had to bite back a demand to have Genos put them back where they belong.

"I- _I—_?!" Or, he would have until he felt something much _bigger_ press against him. "Genos?!"

The cyborg groaned in response, rocking his hips to press the tip of his cock around the opening of his Sensei's pink little hole. "I want to feel you. So hot and tight around me," he breathed, shuddering as he let some of the slick substance dripping from his length coat his fingers for his Sensei to see. "Look…you've made us both wet…" he taunted, smirking as the cherry-rouge flush on his Beloved's face deepened.

Self-lubricating. It would undoubtedly help the preparation process along as well as ease any pain his _lover_ —no " _would_ - _be_ " this time because it was definitely happening tonight—might experience. Not only that, but it also served a second, hidden, function.

One that Genos couldn't wait to try out.

Meanwhile, Saitama was sure what he was experiencing something akin to panic. "W-wait—Genos!" And he was surprised when the other actually did. The hero gulped, teetering on the edge of 'stop' and 'go.' "I…I…"

What should he say? A climax of more than one kind was on the line here…

A response was at the tip of his tongue; a response that Saitama hadn't consciously planned nor a response that he was probably expecting—but a _true_ response nonetheless that only needed his voice to give it meaning and for action to be born from it.

The ringing that anti-climactically followed was not the voice either of them were looking for, however.

And it was so fucking cliché that both of them froze for a few seconds to make sure it was really happening. Upon the fourth ring, however, one of the pair relaxed as the other tensed.

It was quite fortunate that Saitama's quiet prayer of _"Oh thank god…"_ was wholly overshadowed by Genos's forlorn hiss of " _Damnit_ …" as the latter withdrew from his partner to reach for his phone.

"Yes, hello?" Saitama supposed he should feel a little bad for being so relieved when Genos's eyes were literally black with murder. "This instance?" There was a deep scowl marring his face and Saitama lazily wondered what happened. "Right…I'm in the middle of doing someo— _something_ right now." On Genos's end, he did his absolute best to ignore the dark look Saitama shot him. "I'm not sure if I can…" and he looked over to his Sensei, so wonderfully naked with Genos's bites littering his skin before they disappeared within a few cruel minutes. But there were babbles of a certain S-Class Rank 2 ESPer and unnecessary damage and some mutterings about mandatory exercises to reduce collateral damage and in all honesty, it was a _real_ mood-killer.

Saitama sat up with a soft smile. "Hey, it's all right." The disappointed look on his partner's face didn't escape him as the rambling on the phone continued. "You head over. I'm not going anywhere."

There was a sigh at that and before the person on the other line could say anything more, Genos ended the call with a curt, "I'll be there shortly." He snapped the phone shut (with a little bit more force than necessary, if the hairline cracks on the cover said anything) and drew Saitama in for a chaste kiss. And what was Saitama to do but melt against him? He could already feel his skin cooling, the excitement fizzling away as a comfortable warmth overtook the embers of zealous lust. "Come with me?" Genos murmured against his mouth.

Saitama pulled away to give him a look. "Genos, we probably don't have time for—"

"I meant to the meeting, Sensei," Genos replied with a blank stare.

"Oh." Saitama blinked. "Sure." He supposed he should be there for silent support.

Genos nodded, pressing another kiss to his neck. "Thank you."

For Tatsumaki, in the event of her unwitting aid. Saitama nodded. "No problem."

* * *

"You want it to _WHAT_!?"

"I'll have to call you back, Doctor," Genos muttered to his (newly repaired) phone before pressing the red button.

Meanwhile Saitama just continued to gaze in astounded horror at him like he had just grown two heads. "Just…just what kind of weird, kinky stuff are you into?"

And by 'head,' Genos meant the one on his shoulders. Having another one paired with the relatively new appendage south of his beltline was something that hadn't even crossed Genos's mind. "In all honesty, I'm not sure. I'm willing to try anything with you, however," he answered truthfully. _'For you,'_ he mentally added.

It was unfortunate that his Sensei seemed to be even more terrified of that response. " _Just_ —! Argh…what's wrong with the normal stuff?" Saitama demanded, red-faced and looking for all the world like he'd really like to talk about literally anything but this.

Genos nodded in understanding. "I do not mean to say that more traditional methods are obsolete or unpleasurable." Definitely not. Their first (botched) attempt at lovemaking was entirely sensual and gratifying…it was just that they never actually got to penetration. "It is simply a small modification that will prove useful in stimu—"

" _Small_. That's… _small_ to you?" Saitama repeated, disbelieving before quickly shaking his head. "I mean…it's not necessary, is it?"

Genos shifted his eyes away. "Perhaps not entirely _necessary_ …" But it might prove helpful, at least, to have his partner more concentrated in their intimacy to keep the distractions from completely ruining the small moments they had to themselves.

"Yeah. I mean, just…you and me. No fancy gadgets or weird stuff," Saitama insisted. "It may not seem like a whole lot…but that sounds okay to me…How 'bout you?"

Genos gave a sigh. "Sensei…" Did he really need to remind Saitama that he _was_ pretty much _made_ of fancy gadgets?

Saitama seemed to almost fidget in place, white cape billowing behind him. "Look…there's nothing wrong with going a bit slow, right? Or— _tame_. Tame is good," he continued, skittish of the subject as Genos had ever seen him.

The younger gave a nod. "Of course, dearest." Saitama-sensei never ceased to amaze him; how a man so amazing could be so wonderfully modest.

"So uh, yeah. Don't try to go overboard, okay?" he added lamely before heading to the door.

"As you say, my Darling," Genos replied, waiting for the last swish of a pristine mantle to fly out of sight before he pressed the redial button on his phone. "Hello, Doctor? Yes, at least four levels to the vibration intensity."

* * *

"He asked for a _what_?"

"A. Vibrating. _Dick_." Saitama repeated, stabbing the words pointedly.

"Wow…" Fubuki gave a low whistle. "You're lucky."

This was the last time he confided in the younger ESPer. " _Shut uuup_! That's the last thing I want to hear from you!" he groused, burying his head in his hands. "I don't know what to do…"

"Lie back and take it like a man?" Fubuki supplied (un)helpfully.

Saitama sent her a flat look. "For once, your sister's been more useful than you are."

She scoffed. "As if she knew she was helping the likes of you." Still, it was only amusing to see the strongest man wallow in misery for so long. Fubuki sighed. "Look, so what if you're— _inexperienced_ —"

"A goddamn virgin," Saitama corrected, face currently smooshed on the wood of the table.

"That too," she assented, mildly mirthful and somewhat sympathetic. "Look, won't Genos see that as a good thing?" In fact, Fubuki had her money on the cyborg worshiping Saitama's body like it was sacred or something when he found out—well, more so than he already did.

"Maybe, but…" Saitama lifted his head up, considering it for a moment. His brow furrowed before making a miserable face. "I dunno…what if I'm a bad lay?"

Not that Fubuki dared to dwell on it for more than a few seconds, but she _highly_ doubted Saitama'd be bad in bed. Lazy, perhaps, but not terrible. But like hell she'd say it. "He'd never tell you that." The damn cyborg loved him _way_ too much anyways.

"That's what I'm afraid of!" he whined.

Fubuki rolled her eyes, though she did see his point. Sometimes, it seemed like Genos was all-too devoted to the man.

It was a good thing Saitama was worthy of every bit of that unfailing loyalty. "Look, this is my first actual _serious_ relationship. Sure sex isn't everything but I want him to enjoy it if he wants it." He sat up slowly, a single string of genuine emotion resonating in his voice. "It would…really suck if I just took everything he gave me and not be able to give back, you know?"

Fubuki hummed, a hand concealing her endeared smile. "You're awfully considerate about this. It's surprising." But not really. She expected something like this out of Saitama, who became so strong that he rarely had to put real effort in anything but what truly mattered. Not that she'd say that either.

Saitama, meanwhile, looked like he had all but given up in their impromptu consultation. "You're awfully useless right now. It's irritating."

"Fine, fine…" It wasn't exactly often that Saitama would come and speak to her, especially about such a sensitive topic. She might as well give him _something._ "Why not read up on it?" Fubuki suggested. "There's bound to be some magazine articles or websites that can help you out."

Saitama blinked. "Yeah, no. I'd rather eat my left fist," he retorted outright. The younger ESPer could almost feel her patience go up in flames. "And you're deferring me to other sources? You suck at this. I'm gonna find King…the S-Class Group Exercise should have ended by now…"

Fubuki could slap the man. But she had a feeling that she'd only be left with a broken hand for her troubles. Instead, she seethed for a few seconds before voicing her eloquent discordance: "You're honestly going to trust a man who gets draws all his love-advice from his dating sims?"

All right, perhaps it was not as refined as she would have liked it, but it got her point across as Saitama considered her words before sitting back down.

Crossing her arms, she shook her head in quiet consideration. "Saitama, just _talk_ to him. If you're not ready for whatever reason, whether you're too nervous or if you really think that it'd just be awkward for you two later, then speak up." Her voice softened though she shot him a chagrined look. "Genos loves you, you fool. I think he'd rather wait until you're certain than live with the guilt of knowing he went through with it when you weren't one hundred percent sure."

Saitama merely stared back at her, face unreadable as always. "I'll try, I guess," he replied simply.

And any irritation Fubuki held on to quickly dissolved at the murmur of _Thanks_ she received from him, simple and honest, for her troubles.

* * *

Romancing his Sensei took time.

A lot of time, a lot of effort, a lot of patience, a lot of trials, and a lot of errors.

((A lot of courage and a lot of research as well.))

So many sweet nights spent in gentle caresses and sugary kisses before Genos was bold enough to open his mouth and slant it against his Sensei's _just so_ in a heated exchange of pants and moans. Hands that were kept in innocent embraces soon wandered to search against heated skin and titanium plates, shirts lifted and pant buttons undone to reveal more tantalizing flesh and masterpieces of metal. And it was then that they felt the romantic affection blossom and thorn to fevered passion as clothes hit the floor and lips, teeth, and tongues busied themselves with intimate discovery of each other's bodies.

The progression took their delicate time but some nights, Genos was able to experience all the stages in one experience; a simple kiss taking the lead from a flash of affection to bodies writhing against one another atop messy sheets and a cloud of steam.

But tonight, just as all the nights previous, did not lead to their first intimacy. Because tonight, while the moon sleepily climbed to the clouds and stars barely began to light its path, his Beloved Sensei drew back with a gentle smile just long enough for Genos to cherish before giving him a honeyed kiss. He then drew back and happily informed Genos of a sale that day. That they would be able to make it if they hurried and that the store closed three hours from now.

And Genos didn't mind.

Not one bit.

Being physically intimate with Saitama wasn't even an integral part of their relationship. It was a perk, if anything, a small aspect in the midst of all that Genos was able to enjoy now that he and Saitama were officially dating.

Things like being able to hold the man anytime he wanted, feel lean muscles relax against him and to hear that soft sigh like being with Genos was enough to melt his worries away—even for a little while. Like being able to push their futons together on cold nights and fall asleep to strong arms wrapped around him and a face buried in his chest, a body of titanium and wires feeling safest in the embrace of the strongest hero to have ever existed. Like being able to kiss Saitama, not as a heady message of want and lust, but a simple conversation without words that expressed how very precious his Beloved was to him; and when Saitama kissed back, soft and slow, there was no doubt in Genos's mind that he was cherished by the man who had his heart in every way.

And Genos said it so often— _I love you_ , _I love you, I love you_ , painting his Love's skin with every stroke and kiss with those words, valleys and peaks chartered by humble hands, excited to explore His One who gave himself to him; His One who Genos couldn't deserve but had had lost himself to him without even knowing, as easily as Genos was lost in the soundless gaze he received from earth-colored eyes, the call of _It's you, It's you, It's you_ that named him as his Saitama's choice.

It was enough for Genos to have that.

It seemed enough for Saitama as well.

Because from all the times they had been disrupted, he never appeared perturbed; flustered, perhaps, but he never once complained or appeared irritated. Mood effectively ruined and romantic atmosphere dispersed by the chaotic and customary events that made up their daily lives, Saitama regained his footing effortlessly to balance it all while Genos floundered with new-found hormonal urges and a cybernetic case of blue balls.

Perhaps it was because Saitama was twenty-five and knew how to control himself while Genos was nineteen and green.

Because he knew carnal pleasures were so insignificant in the face of what they shared, of what bound them together.

Or maybe it was because his Beloved didn't necessarily want it.

The thoughts were there, lingering in the dark of his mind. They didn't trouble him too much, however. Saitama loved him. He knew that better than his own name.

Perhaps some things didn't need an answer. Or maybe there was more than one to give—convoluted and confounding, just as all of life's questions were wont to be.

Like…did there have to be a sale on _eggplants_?

All right, in reality, there was a sale on a variety of vegetables and select fruit. That was much more conceivable. A sale on vegetables and select fruits that they apparently needed.

Like eggplants, cucumbers, opo squash, daikon radish, carrots, okra, and of course, _bananas_.

And while Genos quietly lamented amid the other shoppers, Saitama continued his bargain-spree, none the wiser. "Make sure you find the biggest ones, all right?" Genos wondered if Saitama preferred a bigger size as an asset to other things as well. But such musings weren't suited for the grocery store, even with all the phallic foods surrounding them both. Once more, it didn't seem to bother his dear Sensei as the man currently inspected another lengthy eggplant for size and quality.

So Genos would hold off on that idea—at least until he knew for sure if pursuing a physically romantic relationship was what Saitama wanted. "Certainly, My Light."

He ignored the grumblings of " _You're the one that keep glows in the dark when I'm trying to sleep"_ in favor of the sweet blush that stained his Beloved's cheeks a pretty cherry red.

Oh, cherries. They should get some of that too.

* * *

His Sensei's lips had been a source of longing and lusting for him in the past.

Genos's own were of synthetic skin, more resistant than the human variant, but plush and supple to the touch. Months ago, he brought the tips of his fingers to press against the soft cybernetic flesh and wondered how different his skin felt compared to his Sensei's. Days after that, the thought of how their lips would feel against one another wormed its way to wayward thoughts and refused to leave ever since.

Even now, he was still chasing after those lips though he had answered that haunting question months ago.

" _Sensei_ …" Genos groaned as Saitama broke for air, trailing after that kiss-bitten mouth.

And when he caught his prize, he was rewarded with a teasing peck and a hard nip to his lips. "I told you not to call me that while we're doing this," Saitama chastised, words already wobbly with want.

To make sure he didn't escape again, a metal grasp on strong hips lifted the smaller body onto his lap without so much as a noise of protest from the other. Titanium alloy and copper wires caged his willing captive while lean legs wrapped around his waist in turn. "Forgive me," Genos murmured, drawing his Beloved in another searing kiss. " _Saitama_ …"

Genos happily swallowed the mewl that managed to slip past his Sensei's guarded mouth, reveling in the small trembles that ran through the blushing hero in his arms.

"You enjoyed that," Genos cooed, licking a wet stripe down his Love's neck.

"You too," Saitama retaliated, grinding on his lap while fingers explored the sensitive little areas around his pelvis unprotected by metal and unprotected from Saitama's dexterous hands.

It didn't take much longer for clothes to be divested, warm skin against heating metal and mere seconds after that for Saitama to be pushed back on the futon, bitten and bruised by fingers and teeth as Genos admired his own handiwork at modern art with his Sensei's skin as a canvas.

He was breathtaking here; skin glistening with a sheen of sweat, chest rising and falling rhythmically from arousal and anticipation, an earthen gaze afire and hazy with need—none other could possibly compare. And only _he_ would be the one to see that face—those sharp features and dangerous eyes heady with want, flushed with desperation for release. Genos shuddered as he knelt between his Sensei's legs, eyes darkened with desire, a loving gaze sweetly poisoned as a thorn of possessiveness pressed deeper where a beating organ should have been.

"Do you want this?" he pleaded, pressing a kiss to a folded knee. " _Darling_ …I need to know."

A smirk on that teasing mouth sent his breath stuttering. "You look troubled, Genos."

"I want…" _I want to have you, I want to make you cry with pleasure, I want to claim you in every way, I want you to be minemine_ _ **mine**_ _—_ "I want to know if you're enjoying this," Genos breathed.

He received a patient smile in return.

Saitama was no fool.

He saw the way Genos looked—how he hungered for him (of all people) like a starved beast. But he asked anyways, no matter how reciprocating Saitama had been, no matter how much Saitama had taunted and teased him in return—no matter how much Saitama made it apparent that he wanted him like no one else…and trusted him the same way.

So Saitama had only one thing to say to that: "Well…I'm hard, aren't I?" He would have added a half-hearted chuckle but at the burning look in Genos's eyes, he guessed now wasn't such a good time. So, instead, there were two things he needed to say: "I want it…" he murmured, soft and low, forcing down a shiver as Genos surged forward, locking their lips together. _Even if I have no idea what I'm doing, if it'll be good for you, or if it'll be good for me in the end, I_ _ **want**_ _it._ And as Genos pulled away, what else was Saitama to do than add a third: "So are you gonna give it to me, or not?"

"If my Master so wishes," Genos replied, eyes gleaming.

Saitama resisted the urge to whap him with a pillow. "Hurry before I change my mind."

Preparation was a blur of hastened breaths, throaty moans, three fingers immersed in tight, feverish warmth, a cyborg-cock dripping lube on the floor, and an incoherent Sensei who honestly couldn't give a damn about the mess at a time like this.

And here he was, between his lover's legs—and _this time for sure—_ as he lathered the head of his cock until it gleamed lewdly under his gaze. "I can't wait to feel you," Genos groaned, positioning the tip against the opening of Saitama's puckered entrance. _God_ he could feel the heat, drawing him, tempting him to drive forward all at once, joined together with his Sensei, to feel the man all around him. It was exhilarating.

"Then don't," Saitama said evenly, eyes giving a honeyed glow. "Come on…let me have it," he challenged.

With a snap of his hips, Genos buried himself within his Sensei, mouth falling open in a silent gasp as he was sure something must have short-circuited, flooding his brain with scorching sensations and delicious pleasure as Saitama arched his back with a wanton cry.

 _No way it could feel this good_ — _absolutely not_.

Genos was somewhat aware that he was holding his Sensei's hips so tightly that it would leave bruises but his Sensei's walls were gripping him tightly in turn, tempting to draw him deeper and deeper until all he could feel was heat and friction. He breathed in a cloud of the steam that sputtered out of him, regaining himself little by little until he was sure he could move without hurting his Beloved.

"Ready?" he murmured, leaning forward to catch the other's lips.

"As I'll ever be," Saitama replied, meeting his mouth half-way.

He rocked his hips gently, trying hard not to get lost in the quivers and quakes of the body beneath him. Shallow thrusts that drove a bit deeper in each time, quiet hitches in breath spilling into the air as Genos brushed against the sensitive bundle of nerves that jolted pleasure down Saitama's spine.

The air between them was molten hot, thoughts were dazed, and he could feel the world crash all around them as he worked a rhythm. Genos had read that sex could be described as an earthshattering moment. But with the way he felt the ground beneath them shaking, the rumbles and clatters falling on his ears, he just didn't think it was taken literally.

"Genos, stop."

And immediately, he did.

Oh.

 _Damn._

He knew better than to get his hopes up. Genos watched, forlornly as Saitama slowly lifted himself up, wincing as his cock slid out of that perfect heat. Still, he couldn't help but feel pride swell in his chest as his Sensei wobbled in his steps to reach the window.

When Saitama drew back the curtains, Genos needed to see only a glimpse before he sighed.

Another monster.

Why was it that when Genos had silently suffered with his previously-thought unrequited feelings, he was made to endure the double-edged sword of endless hours alone with his Sensei, but now that he and his Beloved were finally dating, they couldn't have one _(intimate)_ moment without something popping up and making Genos want to scream?

And unfortunately, not in the fun way.

"Let's go." By the time Genos was done lamenting, Saitama was already in his hero suit and, by the looks of it, the thing rampaging outside had begun some long-winded introduction.

Genos nodded hollowly. "Yes, Sensei."

Saitama paused, unsure if he was feeling guilt or the same burning annoyance at being disrupted as Genos—just to a much smaller degree that the cyborg. Glancing back to the curtains, a flash of fire barraged the beast's back mid-sentence while another attacked flanked it from the side. Some other heroes stepped in to the fight. And while the thought was fleeting and leaning towards the crazier side of his usual schemes…

Saitama took that as a sign.

Before Genos could even pull his shirt down all the way, he was being pushed back onto the wall, Saitama kneeling before him as the hero unbuttoned his pants and pulled down the zipper. "We can take care of that quickly."

Genos, for the life of him, was quite sure he was short-circuiting again.

Saitama fumbled a bit with the compartment and gave a small noise of satisfaction as it opened, revealing a thick cock, hardened and dripping with what looked like precum. It felt heavy in his hand, soft to the touch as he gave tentative and experimental strokes along the shaft. He hummed as Genos's knees buckled and a hiss of steam erupted above him. _'I have no idea what I'm doing but here's hoping I do it well.'_

Without preamble, Saitama took Genos in his mouth.

" ** _SENSEI_** _!_ " Did he scream? Genos swore he screamed. Hell, the people outside, miles away with a rampaging monster upon them would have confirmed it. And now he was overheating. Overheating as Saitama licked and sucked, palming where his mouth couldn't fit all at once as a hot, hot, _hot_ mouth engulfed the head of his cock, tongue teasing the slit. Oh god—he was going to shut down—shut down and drown in error messages at the hottest image he had ever had the fortune to witness: his Sensei, fully dressed in his pristine hero attire, on his knees and sucking him off. Seeing those lips that haunted his desires for and daydreams wrapped around the cybernetic flesh as artificial neurons fired and frayed from the delicious attention given to them from Saitama's hands and mouth.

It was a miracle he could still stand.

"S-Sensei, I— _ah_!" he gasped in a breath, bracing himself behind the wall (careful not to leave too many cracks on the sheetrock). Below, Saitama tried to give an apologetic look but with a mouthful of cyborg cock, Genos could only clutch at the white cape over his shoulders to keep himself grounded.

' _Sorry if I'm being a little rough_.' Saitama hummed in thought, though Genos really seemed to enjoy it. If the grip on his cape urging him to take in more of his length was any indication anyways. So Saitama indulged him, opening his mouth wider. It was worth it to hear that intense whirring alongside Genos's groans and grunts. As the tip pressed against the back of his throat, however, Saitama drew back to let his fingers play and tease, red gloves in stark contrast against the black material. He focused on the head, alternating between pressure from his swirling tongue and suction to see what exactly Genos liked.

He couldn't exactly ask Genos right now anyways. The poor guy was barely stringing a coherent sentence together.

"Sen- _Sensei_ I can't a- _AH_!" It was beyond words—earthshattering was too mild a term. And Genos was fairly sure the monster rampaging the streets had nothing to do with it this time. He clutched the sturdy cloth in his hands, gasping and trembling as he felt something indescribable was approaching its peak. And when one final swipe of a sinful tongue drove him over the edge, the second function of his self-lubricating cock triggered before a single word could be uttered of it in warning. He felt Saitama release him with a wet pop and Genos had to remember how to keep himself upright as he attempted to articulate his words once more. "I'm—I'm sorry, Sensei…I tried wa-warning you…"

Saitama looked up at him, face a mix of curiosity and blank shock, tongue coated in the thick, viscous substance. "This lube…it's edible, right?" Genos very nearly overheated as some of it dribbled down his chin.

"Yes…" he croaked.

Genos was afraid his sensors might have failed him as he shamelessly watched the Adam's apple bobbing as Saitama swallowed down his load. He bit back a groan as a pink tongue poked out of his Sensei's lips to taste the corner of his mouth. "Strawberry flavored?"

"You prefer it," Genos explained breathlessly.

And his Darling—his gorgeous and wonderful Darling gave him a lopsided smile, face red with embarrassment while his voice lilted sarcastically. "You're so good to me." And Genos knew he'd do anything just to have Saitama make faces like those more often. "Hm…you know…I guess the kinky stuff is okay. And the fancy gadgets." He stood, looking for all the world like he had not just given Genos a blowjob—and a sky-splitting orgasm—and began towards their door and to the villain of the week. He paused, turning back to Genos. "But like I said, don't go overboard, okay?"

"Sensei…" And before Saitama had the chance to slip out the door, Genos pinned him against his body, a hungry mouth licking away the remaining lube Saitama hadn't been able to reach until he reached his lips. "After this fight, I'll be sure to return the favor."

Saitama's knees buckled.

* * *

Unfortunately, he wasn't able to live up to his promise.

Still, while he was being repaired at the Doctor's, it was a good time to bring up his ideas for upgrades. He'd add in the size enhancement to his list as well.

* * *

Saitama heard Genos approach without even lifting his head from the newspaper in his lap as he marked down another date for a sale. "Oh hey, welcome ba—"

Genos, however, wasted no time in ravaging the other's mouth. "I believe I owe you," he growled, low and hungry as Saitama's blush bloomed attractively to the tips of his ears.

The hero blinked, a nervous reaction triggered by the smoldering gaze he was trapped under. "Haha…now?"

It was a good thing Saitama was so used to the various frightening expressions on Genos's face. This one was only mildly frightening. "I just scouted through every street, scanning for and seeking every potential danger and disaster that dares show its face, even in the neighboring cities." As he spoke, he loomed closer and closer over his teacher. "I took down three tiger-level threats and one demon-level. Now it's quiet and I finally have you where I want you."

Saitama blinked, a blank face and a befuddled smile concealing the inward panic and arousal starting to pound in his ears. "And…where would that be, exactly?"

* * *

Apparently on his hands and knees.

"Patience, Beloved," Genos cooed, peppering kisses down his back as he pumped his finger in and almost completely out of Saitama's scorching walls.

" _Ngh_ —easy for—ah!—you to say," he groused as Genos curled his index finger, wringing out a low moan from his throat when it teased against his prostate.

In actuality, it wasn't. Having his Darling presented so lewdly in front of him was having detrimental effects to his mental state. But he wouldn't let Saitama know that. He added in a second finger, stretching the tight walls further. "You're already trembling for me and taking my fingers so well." He gave a light press to the gland, swollen with arousal. "It's like you're hungry for me."

Saitama jerked under the touch, a rough gasp torn from his throat. "S-shut the fuck up and get on with it." The sound went straight to Genos's cock.

"In a while," Genos murmured, transfixed by the way the pink hole twitched and started to suck his fingers in the tight heat when he began to withdraw them. The lubricant made obscene noises as he teased the opening before he pulled his fingers out. "Raise yourself up some more." Genos licked his lips. "I want a taste."

Maybe in Saitama's lust-fogged mind, doing what he was told was a good idea.

Saitama had yet to decide if that was a big mistake or not.

He was about to find out. " _Gghh_ — O-oh _god_ —" That wasn't' a finger. Definitely not. "G- _Genos_!?" Saitama tried squirming away but there was a tight grip on his hips to keep him still as pleasured moans escaped from his mouth. A slick tongue pushed past the first ring of muscle caused Saitama to cry out and yes this was a big mistake.

Oh fuck—

 _Oh fuck._

It was so wet. Wet and thick, moving inside him, exploring him thoroughly as he felt Genos press further in, teasing and thrusting his tongue through the tight passage. Saitama's arms nearly gave away and he was fairly sure his blush had reached all the way to his ass by now. It was actually surprising that he still had blood left after he was fairly sure it had all flocked south, the evidence heavy and dripping precum between his legs. He bit back what might've been a scream when Genos started moaning into him, the slick muscle reaching in farther than before, like he couldn't get enough of his fucking him with his tongue.

That's it.

He can't—he just can't—

 _"_ _G-god_ _ **JUST DO IT ALREADY!**_ _"_

The wet sound that followed as Genos pulled away was downright pornographic. Even more so with lubricant dripping from his mouth. "Are you sure? You're still so tight," he remarked, fingers spreading the twitching hole.

If Saitama were any less of a man, he would have probably sobbed from sheer frustration. " _Goddamnit_ , I'm a virgin but I'm still _me_ —I'm pretty damn sure I can handle a bit of pain!" _Fuck_ this was mortifying—but it felt so good, the finale better be worth it.

The movement behind him stilled for a good few seconds and Saitama craned his neck to find Genos, in speechless awe. He was about to question it before Genos spoke, voice devoid of any emotion: "…You're a virgin?"

 _Goddamnit_. "Uh, yeah? Didn't you…?" Saitama froze as Genos suddenly ducked his head, blond bangs concealing his eyes. "Uh…Genos?"

"I'm going to be your first?" he asked, voice barely above a whisper.

Saitama glared at him. "Yeah, if you ever get around to it." He frowned when Genos just sat there, completely motionless. "What are you…" His eyes widened when Genos lifted his head. "Oh hell no— _Genos_!?"

Fuck. He looked like he going to crying oil again. "I'm…so honored, Sensei." His eyes were practically glittering, holding back what Saitama suspected were tears of disbelief (and joy).

Saitama inwardly groaned. Ah great…he was back to "Devoted Disciple" mode.

Or…at least a sexual variant of it from the way he seemed to lock on to his target, eyes blazing with determination. "Please, do not worry—I will treat you well."

Well, at least they were finally going to get on with it. Still…" _Man_ you're embarrassing."

Genos paid no heed to that and instead let his eyes travel to the marks littering his Sensei's skin—bites and bruises in shades of purple possession and red lust, marked for Genos's eyes. "Please turn over," he demanded more than asked. "I want to see Sensei's face when I pleasure him." And to know that what came next, that no one else had ever seen Saitama this way—seen him lost in pleasure, felt the delicious grip of his walls, or hear the way he cursed and cried for more—all for _Genos_ —

 _It was_ _intoxicating_.

Unaware of all this, Saitama complied, grumbling all the way despite the ravenous gaze that fell on him. "You're so fucking embarrassing," Saitama whined, even as Genos laid him down, kissing and nibbling flushed flesh from his stomach to his thighs.

And as always, Genos ignored the small quip. "Before we continue, me know if you're in _any_ way uncomfortable—"

Saitama sent him a flat look. "Genos, you teased me for nearly a goddamn hour; I already came _once_." He repressed the shudder at the remembrance, those gold eyes pinning him beneath their gaze as Saitama came undone in his hands. "So are you gonna use your cyborg dick or do I have to take it from you and do this myself?"

Genos smiled, reaching down to give him a kiss. "As you wish, Saitama-sensei."

Holding his thighs to lift up his Beloved's legs, Genos licked his lips as the sensations came back to him—the friction, white hot and overwhelming as he drove deeper and deeper within his Sensei's body, the ecstasy of their physical union a narcotic that had Genos hooked the very first moment Saitama pressed his lips against Genos's own.

His cock was dripping, black material almost glistening in anticipation as he lined it up to his Beloved's entrance, smearing the pink hole with his 'precum'; he nearly lost himself when he looked to his Saitama's face, cheeks rosy with desire and eyes darkened with want, mouth whispering a simple command: " _Go_."

Genos thrusted in, slowly, breath breaking in gasps as Saitama hissed in burning satisfaction or from the satisfying burn. Saitama was damn sure that Genos wasn't even in all the way but the feeling of being filled, inch after inch of slow digs to help him adjust to the size, made his heart tumble and breath stutter in triple time. There were gasps and groans from both of them as Genos rocked his hips in deliberate movements as Saitama nudged his hips forward, meeting the thrusts in a sloppy rhythm that went just too slow for Saitama's liking.

"You can move— _faster_ ; it doesn't hurt and—"

Saitama gave a soundless cry as Genos pushed in unexpectedly, fully sheathed in his quivering body as metal fingers gave a bruising grip to trembling thighs. He fought for breath, feeling so full at the overpowering and feverish sensation of Genos pressed up against him, cock buried inside him, and Genos—gorgeous and everything Saitama knew he didn't deserve—above him, losing and catching his breath, eyes consumed with need, and positively steaming with want.

 _It was intoxicating._

"Genos…" Saitama murmured, wincing as a flash of pleasure teased down his spine as the cyborg brushed against the sensitive bundle of nerves within him.

"I…apologize, Beloved…" Genos gritted out, mechanical body shuddering. Back bowed and blond head resting on his shoulder, Saitama listened as the whirring of his core rang in high pitches; heavy pants fell on his ears and faint sparks fizzled and flew from his joints as Genos held his position in dedicated desperation.

Oh. Saitama forced back a grin. "Close to coming, aren't ya?"

" _Yes_ ," he groaned. "Like you said, I teased you for an hour. And I haven't come yet."

Feeling just a bit impish, Saitama rolled his hips, feeling Genos's restraint starting to snap. He guided Genos's face to meet his own and leaned up, murmuring against a gasping mouth: "Well now's your chance, right?"

Saitama saw was a flash of fire in those eyes of gold as his control crumbled.

The kiss felt like fire; explosive passion and overflowing fervor as Genos drew back and slammed his hips forward. And Saitama loved it. Every time his cock drove into him, filling him up so well as near-brushes teased his prostate and left him hungering for _moremore_ _ **more**_ of Genos, more of feeling himself overcome and overwhelmed with that raging fire as the pace turned animalistic, a cry or a sob wrung out of Saitama's kiss-bitten throat when Genos angled himself to rock against the one spot that made stars dance and crash before his eyes, eventually losing himself to shameless moans as Genos continued to drive into him, fervidly, forcefully, ferociously.

"G- _Gennnos_ …" Saitama felt the sheets tear beneath his hands. "Ah- _ah_ —!" It was a good thing he wasn't clutching onto Genos's (dented) back this time.

"Y-you feel amazing…My Love." Saitama almost groaned. He wished he could turn away because it apparently wasn't enough that his ass was being pounded by the guy—no, Genos also had to look at him with those damn adoring eyes like Saitama was the most precious thing in the world. And of course, he also had to take Saitama's hand, previously clutching the remains of their blanket, to lace their fingers together, tenderly and lovingly. "Sweeter than sin…more pleasurable than paradise."

Saitama wanted to laugh but with the way Genos was thrusting into him, even at his slowed pace, it would have made him sound like he was sobbing instead. "Pfft…you're a fucking sap."

And Genos kissed him, long, deep and perfect. "That I am."

It took maybe a second or ten before: "…if that was a pun, know that I've never been more proud of you."

Also never been more aroused but that was something Genos didn't need to know about. But it was nice hearing Genos laugh like that—body shaking against him as his bangs tickled the curve of his shoulder. Their rhythm slowed further and Saitama basked in the warmth of the body above him, feeling them move with one another in such an intimate way, something in his chest swelling at how they fit together like they'd always belonged. So Saitama kissed him again, a _thank you_ and an _I love you_ all at once while Genos's lips kissed back in a gentle _I know_.

But peace never lasted long—call it entropy but Saitama figured it was more like Genos's metal abs were rubbing against his dick causing him to clamp down on Genos's cock in turn, making the cyborg above him hiss in pleasure and thereby causing him to hunger for more of that sweet friction. And the leisurely pace was soon stolen away by a frantic need, a frenzied heat that singed all the way to the tips of their toes as Genos slammed into Saitama's greedy body, hand between both their stomachs to stroke and tease his Beloved to completion.

And Saitama—in the midst of it all—bit his lips as he teetered between pleas for mercy and cries of damnation.

But what instead sounded was a loud heartbeat from the hallway.

" _S-Saitama?_ " Said hero's eyes flew open to find the hand on his cock missing and instead glowing bright red and aimed at—

"King, _move away from the door!"_

There was some fumbling behind the entrance. " _B-but_ —"

" _FORGET WHAT I SAID!_ _ **GO**_ _!_ " And as the thrusts faltered and Genos looked back at him with accusing eyes, Saitama added: "And thanks for putting up with me!"

" _Y-you're welcome—er, have fun!_ " There following that was the heavy thud of footsteps. " _Bye_!" The slam of a door was the end of that.

Saitama blinked, looking up at Genos with a blank expression. "I'll explain later but uh…you'll be glad to know that there won't be any more interruptions. Unless something else pops up like another monster or—"

Saitama had to clamp a hand over his mouth as Genos continued, his pace relentless to drive his Sensei to the heights of heaven or pound him 'til the floors gave out.

"G- _GENOS_!" Damn that brat. He just had to move his hand out of the way, malicious black eyes dark with desire as he leaned in and whispered some bullshit about wanting to hear every little sound he made like he didn't just intentionally flip a switch somewhere to turn his dick into a _fucking_ _ **vibrator**_. The _nerve_ of that brat.

But oh god it felt so _good_ —and so weird—feeling it hit his prostate dead-on with enough intensity to make such embarrassing noises spill from his mouth, felt so good as Genos—the _fucking_ _ **brat**_ —pressed it right against the abused and sensitive spot inside him, vibrations threatening to snap every single strand of sanity Saitama had left as he screamed his throat raw.

Felt so good as Genos started rambling well over twenty words in his ear of _Sensei, you feel so good, so tight and hot around me, eating me alive like you're hungry for more, you're so good to me Sensei, I'll give you everything you want and everything you deserve, let me hear you, let me hear you want me, want me and no one else, look only at me, only me, know you're minemine_ _ **mineMINE—**_

" ** _YOURS_** **!** " Saitama cried out, colors and sensation collapsing and crashing all around him, something breaking as he shuddered into Genos's embrace, metal arms holding him together as he fell apart.

And when Genos followed, smashing their mouths together in a bruising, claiming kiss, Saitama moaned as he felt the lubricant fill him, trickling from his entrance as it overflowed down to the mess on the floor.

"Mine," Genos asserted once more, murmuring against his lover's lips. "And _yours_."

* * *

"You orchestrated a few of those times we were interrupted, didn't you," Genos asked, mouthing a few kisses on Saitama's bald head.

"Yep," came the simple reply as he shifted against the metal body he was currently being crushed under; not that he minded really.

"And you were afraid that, because we were a virgin, you wouldn't know how to pleasure me in return," Genos deduced, nuzzling into the crook of his neck.

Saitama sighed as he carded his fingers through blond stands. "…Yeah."

"…Tatsumaki?"

Saitama scoffed. "Coincidence."

"Good," he breathed. "And King?"

"Not my fault you leave your diary open and mark down the dates you plan on seducing me."

Genos smiled against his skin. "Fair enough." He wrapped his arms around him, lightheaded, drunken and dazed with the man he loved in his embrace. This was what he lived for—for the rest of his days to have nights like these. "You are so, _so_ very precious to me," he murmured, heart swelling and core whirring with heady adulation.

"I know," Saitama whispered, patting his head as the body above him practically purred with affection. "I love you too, Genos." A beat later, his eyes widened.

 _Shit_.

The last time he said that, Genos wouldn't let him get an ounce of sleep, the affectionate sap.

But to his surprise, no loquacious ramblings followed, nor tearful proclamations of eternal devotion and loyalty, no soliloquys of impossible things that Saitama was grudgingly starting to believe—words like _forever_ and _destiny_ among a plethora of other romantics. Instead, there was merely a tune humming from Genos's mouth and a song upon his lips: " _Tell me that we belong together—_ "

Saitama snorted. "You're _such_ a sap." He was touched too—no denying that however.

" _Dress it up with the trappings of love_." He took Saitama's hand in his, lacing their fingers together; of flesh and bone—raw, undefined strength, and of machine and wire—fire and destruction wrapped gently around one another in something so pure and true. " _I'll be captivated, I'll hang from your lips instead of the gallows of heartache that hang from above_."

Saitama gave a single kiss to the back of a metal palm.

All the while, Genos sang, from the depths of his core to His Heart entwined in his arms. " _I'll be your crying shoulder; I'll be love's suicide; I'll be better when I'm older; I'll be…the greatest fan of your life_."

"That much is obvious," Saitama scoffed, cheeks cherry red but unable to even bury it under a pillow at this point as Genos started pressing kisses wherever his lips could reach. "Is this how you are after sex? You start singing old 90s hits?" He gave a sleepy grin as Genos continued to sing, voicing along the verses as they came to him: " _And rain falls angry on the tin roof as we life awake in my bed; You're my survival; You're my living proof my love is alive and not dead,"_ completely unsurprised as Genos leaned in for a kiss on the lips.

He smiled, content and complete as he listened to his lover hum the words in and out of tune. "That much is obvious…My Saitama."

* * *

 _Tell me that we belong together,_

 _Dress it up with the trappings of love_

 _I'll be captivated,_

 _I'll hang from your lips,_

 _Instead of the gallows of heartache that hang from above._

 _I'll be your crying shoulder,_

 _I'll be love's suicide_

 _I'll be better when I'm older,_

 _I'll be the greatest fan of your life_

* * *

Notes:

 _"_ _I'll be"_ – Edwin McCain. This is totally their song.

Genos's singing habit is a reference to Bender (from Futurama) and his reaction to having a magnet stuck on him; it makes him sing folk music uncontrollably (being a folk singer is a dream of his). Genos just gets really sappy in his post-coital daze and serenades Saitama with cheesy love songs.

I live for them being stupidly in love with each other orz

Forgive me.

*= In Saitama's apartment (his old one, anyways; I don't know about the layout in his new place) there's the main door, a hallway, and a door that leads to the main room. King got in from the main door (Saitama probably gave him a key or something to let King take back the games he lent to Saitama (and the ones Saitama steals) and was standing in the hallway. Also why King can hear Saitama and Genos so clearly.

*= Reference to the Delta Episode of the Pokémon ORAS games taken from this tumblr post: post/134075267734/shit-that-actually-happens-in-pokemon-a-giant

Genos did get a size upgrade before they had sex; it's just that Saitama really didn't notice (he probably felt it though). And just sayin' it was studied that most people prefer girth over length. Just…throwing that out there.

Note on grammar: Beloved (and a few others) were capitalized in this case because I was using it as an appellation, much like "Sensei" (which I always capitalize). I wrote it not just as a term of endearment but a title Saitama holds to Genos. But as I've been advised, it seems that capitalization is more stylized here and doesn't necessarily need to be (but I do want to capitalize it). But if y'all wanna fuss 'bout grammar, I'll change it :v

-throws confetti in the air- I quit this fandom.


End file.
